Mainframe Computing

Welcome to our new home at the historic Tivoli Theater! Please check our details for access to the space on [our website](https://www.hacdc.org/visit/). Join the discord for questions / help getting in (use channel #let-me-in) [https://discord.gg/dNjuNhNmeT](https://discord.gg/dNjuNhNmeT)

Come in and sit down at a table to play casual MtG Commander!

7:45 PM – Beginner Bachata 8:30 PM – Beginner Salsa This Class is for absolute beginner and up. [Book Your Class Here. ](https://crowndancestudio.com/group-classes/) Choose the date. then Click "book now." $18 Per Person for 1 Class $25 Per Person for 2 Classes Do I need Partner? NO Is it a Series? No. But we review similar materials on the consistent basic. Can I drop-in? Yes. Membership & Class pass available for your better growth and progress. [www.crowndancestudio.com](https://l.facebook.com/l.php?u=https%3A%2F%2Fwww.crowndancestudio.com%2F%3Ffbclid%3DIwAR2zhtlRxGhExkt_lh7UddK-BeWO8Qs1-EOyoeOGv-J3T0iFQh1Mcj2yiCA_aem_AcwNtPvUfkDahcWu-o_1owBvR7kH5cPtGKRaZN0cwvsy7zAKFAW0zv11GyJZeHFK3sXTqcwkHzYjvnhIdj_bZzn9&h=AT03tOQ7TaMbm8BWrbY5GVWwm5AUCbspa2tH6WSZj2P19MdXsK-Ih8hbVRlM9y0i0DuAMcN1QoF5tRzsQ-8aq-F0hneUu0Qayohk--xGdi4ODLmv7dW1y3B0veXR6xDUMxTNH1ui5a1qQMb1Cw&__tn__=q&c[0]=AT23QwS2XzF8mb_UChFebvxb_ZwrfUwkBaJHK5_0MHCyY9o9eHFqWNQPS2IJpCgWWS7KJfldFCk2N1JPAXQQGplryaicqsu-5Hpj0tsphsZ3balIXhHgvlOSxKBXhiUaH8GLAXguklvbM9QOeUG2qAJKdQJ6) Address: 2820 Dorr Avenue Fairfax, VA 22031 See less

Event hosted by Bowie! Please check out our COVID restrictions at: https://wiki.unallocatedspace.org/wiki/index.php?title=COVID-19_Reopening_Plan Monday evenings, we will be open for Project Night - a night to work on, collaborate on, or brainstorm on whatever projects you're currently working on or interested in. Don't have a project? Come see what others are working on and get involved or get ideas. If you have an concept for a group project, bring your ideas and seek out others to join you. Project Night is a great opportunity to make progress on your projects as a regularly scheduled event. Anyone is welcome to work on projects any time the space is open, but a dedicated night--just for this--is really fantastic. Teach, Learn, Build.

What3words: https://w3w.co/stick.juices.rings [https://what3words.com/stick.juices.rings](https://what3words.com/stick.juices.rings) Share only your very best, most interesting shots after the field trip, and keep it down to between 5 and 10 photos. [http://www.fairfaxcounty.gov/parks/huntley-meadows-park/](http://www.fairfaxcounty.gov/parks/huntley-meadows-park/) From the parking lot near the visitor center off Lockheed Blvd, there is Cedar Trail which is about a 15-minute hike to the Heron Trail boardwalk. The Cedar Trail goes through a great forest that has some wildlife like deer and many birds, The Boardwalk is where the majority of the wildlife is located. The Group has seen deer, foxes, beaver, snakes, frogs, green tree frogs, huge snapping turtles, and many types of birds including Bald Eagles, Osprey, Marlins, Great Blue Herons, Great Egrets, King Fishers in the marshy wetlands. The boardwalk can become crowded before sunrise. The crowd, notwithstanding, the early arrivals have been rewarded with sightings of foxes and Bald Eagles. There is a point on the boardwalk that splits. The left side features sightings of shorebirds snapping turtles and beavers. The right side leads to one of the smaller overlooks and has several benches along the way. In the wintertime, the Group gets to photograph many migrating ducks, such as Green-winged teals, Northern Shovelers, and Northern Pintails! In the springtime, the park provides bird boxes for the Wood Ducks and Mergansers to lay and protect their eggs until their offspring fledge and leave the nest. The Group then continues around the boardwalk to the right towards the forest where Great Blue Herons and Red-winged Blackbirds are photographed. Next, the Group approaches a two-story overlook complete with benches for the Group to rest and survey the park. Following a brief respite, the Group continues to Marker 8, the end of the boardwalk. At this point, the forest reappears. And on that edge of the wetlands, there are Red-Headed Woodpeckers. This is one of the few places in the Washington, DC area where they live. After a couple of hours on the wetlands, the Group retraces the route by continuing on the boardwalk to the right towards Cedar Trail, past the visitor center onto the parking lot. There is a small pond behind and to the south of the visitors center that frequently has small frogs. While they are a true find to photograph, mosquitoes have been known to swarm at the pond! The north side of the visitor center features bird feeders that attract hummingbirds and other small birds. At the end of this field trip, the Group typically has breakfast at IHOP, 7694 Richmond Highway, Alexandria, VA. 22306. By sending in an RSVP and joining this meetup event hosted by the Virginia Beltway Photography Meetup, I am also agreeing to the terms of the following release and waiver of liability, which shall be binding on my heirs, executors, administrators, successors, and assigns. In consideration of my (and my child’s) participation in the Virginia Beltway Photography Meetup, I do hereby release, discharge, and hold harmless the Organizer, its members, officers, directors, employees, and the leader(s) of this event from any and all liability by reason of any damage, loss, expenses, or injury arising from my (and my child’s) participation in this event, including that caused solely or in part by the fault of any and all of the above-named parties.

​**Due to the popularity of the event, registration is requested at [https://luma.com/dcmahjongg](https://luma.com/dcmahjongg).** We do not use the RSVP system on Meetup. **A drop-in game every Monday at the Martin Luther King, Jr. Central Library, located at the corner of 9th and G Streets NW.** **==> THESE MONDAY GAMES ARE FOR EXPERIENCED PLAYERS ONLY -- THERE ARE NO INSTRUCTORS ON SITE** <== The Gallery Place Metro station (9th Street entrance) is located across the street. Street parking is available. We play in the Great Hall -- as you enter the library, we are on the right of the room. Games begin at 6:00. Games wrap up at 8:00. **If you own a mah jongg set, we encourage you to bring.**

**REGISTER AT THE LUMA EVENT PAGE!!!** https://luma.com/27ja5gwl Join us for an exciting talk by Mary Gibbs, Senior Applied Scientist at Relativity. ​ ​**​Agenda:** ​​6:00 - 6:30 PM - Welcome and mingle 6:30- 6:45 PM - Introductions 6:45 - 7:30 PM - Talk 7:30 - 8:00 PM - Wrap up **​​Description:** ​If you have ever shipped a model, watched your metrics improve, and later learned from your users that something was wrong, the metrics were always wrong. You just didn’t know it yet. An evaluation consists of three components, a benchmark, a scorer, and a claim about what a score represents. Each component has its own weaknesses. Benchmarks can suffer from narrow coverage, contamination, or saturation. Scorers are often chosen for ease of automation or computation rather than for their alignment with user outcomes. And the claim connecting a score to reality is rarely made explicit. These gaps compound across the model development lifecycle. When metrics improve, teams treat that as a signal and optimize directly against it, which is how a measurement problem becomes a model problem. This talk maps where evaluations can go wrong, considers counterarguments, and ends with practical advice for building better ones. **​Speaker Bio:** ​Mary is a Senior Applied Scientist at Relativity, tackling data science challenges in the e-discovery and legal tech space. She is also an organizer for Women and Gender eXpansive Coders DC (formerly Women Who Code DC), fostering a community dedicated to empowering women and nonbinary individuals to excel in their careers. Mary's experience spans various domains. She has developed data science solutions related to job search and career progression at Teal, cybersecurity challenges at LiveAction Software, and commercial and government consulting at Mosaic Data Science. Before venturing into the field of data science, Mary conducted and published research pertaining to the cellular and molecular mechanisms underlying neurodevelopment at the National Institutes of Health. In other words, she has dissected and imaged a lot of fruit fly brains. She holds a M.S. in Data Science from The George Washington University and a B.A. in Biological Sciences from Cornell University

We connect you with up to 30 Men or Women tennis partners close to your PLAYING REGION and skill level. This program is less competitive, no champions crowned, no league standings just dedicated tennis partners who want to meet up with you on the courts. Players will meet up to play a tennis match or just to hit around. Just go through the [Join Page](https://www.tennisdc.com/partner-program) to enter this program. [https://www.tennisdc.com/partner-program](https://www.tennisdc.com/partner-program)

[Book Your Classes by Clicking This Link! ](https://crowndancestudio.com/group-classes/) Friday: Advanced Expression End the work week with high-energy **Advanced Rhythm** from **7:00 PM to 8:30 PM**. This session dives deep into the technicalities of Latin and Ballroom styles like Rumba, Samba, or Mambo, designed for dancers who value precision and artistic expression. For $25, you'll receive intensive instruction that pushes your physical boundaries and refines your competitive or performance edge in a high-vibe atmosphere. **When: Every Friday** **Time: 7:00 pm to 8:30 pm.** **1 Dances per month:** **\*Please check the flyer on the group class page for the dance of the month. Or contact us to find out.** **Cost:$25 per person for 90 min.**

Come and join Northern Virginia porcelain artists. We will provide all the paints and materials needed. Just bring your smile and creativity. We paint from 10:00 am - 2:00pm every Tuesday & Wednesday. Please RSVP in advance if you like to join oir group. Text: 703-906-9150 We are located few minutes from Tyson’s corner in McLean.

NOTE: This working session is at Lamond-Riggs Library not MLK. It is near the Fort Totten Metro Station. A game development **Working Session** involves 3 key parts: 1. Tell people what you're going to do 2. Actually do stuff 3. Show people what you did **What to bring**: Laptop, Charger, maybe a power strip if you have one handy, any other game development tools you need. Try to download any software you need before the working session. There is Wifi at this location, but it may be slow if you have to download any large files.

Join us for MORE Women's MTB Ride at the Cabin John Trails in Potomac, MD. Beginner-level riders are welcome and encouraged to join in the fun! A mountain bike in good condition and helmet are required. **Sign up at Golden Volunteer here:** [https://x.gldn.io/e/jgkrtQUn21b](https://x.gldn.io/e/jgkrtQUn21b) ***Please do not sign up on Meetup! If you do, you won't be alerted if the ride is cancelled!*** **Meet** at 6:00 PM with wheels down at 6:10 PM. We will not ride if the trails are wet or muddy. Check your email from Golden Volunteer in case the ride is cancelled due to weather/trail conditions. **Description** \- The event is open for women age 18\+\. You must sign a waiver on the Golden Volunteer link\, wear a helmet\, and be able to comfortably ride your mountain bike\. We expect to ride about 4\-5 miles on single track natural surface trails\. Bring your mountain bike\, helmet\, and drinking water\. This ride is **not suitable for hybrid bikes**! As space is limited, please update your RSVP if you cannot attend. **And support your trails and join MORE! www.more-mtb.org** **Where** – Meet at the parking lot for the Cabin John Group Picnic Area at 7701 Tuckerman Lane, Potomac, MD. Follow Google Maps at: https://goo.gl/maps/aumXoQnD2qAp3iNp9

There is supposed to be a let up in the seemingly incessant rain. Let’s take advantage with a walk at Brookside Gardens. We will meet to the right of the visitors center. If anyone is interested we can go to lunch afterwards.

**Important time note:** Please plan on arriving between 5:30 and 6:00 as the elevators lock after 6 and you'll need to message us and we'll need to come get you. The building address is 4450 Bridge Park The entrance is 6620 Mooney St, Suite 400 You will need to scan your ID at the door to get a visitor badge. **Abstract** Like it or not, AI agents are now capable of turning a quickly written paragraph of requirements into a pull request that is ready to be integrated into real-world production applications and it's now our responsibility to make sure AI doesn't go rogue and take down prod - or corrupt our data by misunderstanding the requirements or our existing schemas. In this session we'll explore strategies to protect our codebases through unit and integration testing, documentation, and code review along with additional ways of providing context and guard rails to our AI agents as they carry out the work we've assigned them to do. By the time we're done, you'll have a firm grasp of the problem and understand some helpful options for protecting your codebase from vibe coding mishaps getting YOLOed into prod. **YouTube Link** TBD

We connect you with up to 30 Men or Women tennis partners close to your PLAYING REGION and skill level. This program is less competitive, no champions crowned, no league standings just dedicated tennis partners who want to meet up with you on the courts. Players will meet up to play a tennis match or just to hit around. Just go through the [Join Page](https://www.tenniscolumbus.com/partner-program) to enter this program. [https://www.tenniscolumbus.com/partner-program](https://www.tenniscolumbus.com/partner-program)

Couldn't make Knowledge? Or want to debrief the dancing robots or Autonomous Workforce? Join us for a Knowledge '26 recap, insights sharing, a couple rounds of golf, and fun at Topgolf. As always, drinks and food will be provided. More details to come — mark your calendar, RSVP, and save your spot today!

**History** The [Franklin Park Conservatory](https://www.fpconservatory.org/)’s roots trace back to 1852 when the Franklin County Agricultural Society purchased 88 acres of land to host the Ohio State Fair. After the fair moved to its permanent home, the city of Columbus transformed the grounds into Franklin Park in 1884. This transition shifted the space from a temporary event site to a dedicated public green space for the growing community. The park became a central hub for outdoor recreation and early civic gatherings in the neighborhood. In 1895, the landmark Victorian-style Palm House opened its doors, drawing heavy inspiration from the Glass Palace of the 1893 World’s Columbian Exposition in Chicago. This iron and glass structure became an immediate icon, housing exotic plants that residents would otherwise never see in the Midwest. It remains the oldest part of the facility and serves as a primary link to the conservatory’s 19th-century origins. For decades, it stood as a singular testament to grand horticultural architecture in Central Ohio. A major turning point arrived in 1992 when Columbus hosted AmeriFlora '92, an international horticultural exhibition. This massive event prompted a $16 million renovation and expansion, adding significantly more greenhouse space and the Dorothy M. Davis Showhouse. The festival put the conservatory on the international map and fundamentally changed its scale and ambition. Following the event, the facility transitioned from a city-run park to a private, non-profit organization. In 2003, the conservatory’s identity was further defined through a long-term partnership with world-renowned glass artist Dale Chihuly. After a successful exhibition, the Friends of the Conservatory purchased most of the glass installations, creating the largest permanent collection of Chihuly’s work in a botanical setting. These vibrant glass sculptures are now woven throughout the biomes, blending art with nature. This addition helped cement the conservatory as a premier cultural destination rather than just a botanical garden. Recent years have seen the site expand beyond the glass walls to emphasize community engagement and outdoor education. The 2018 opening of the Scotts Miracle-Gro Foundation Children’s Garden added two acres of interactive landscape designed for hands-on learning. The Scotts Miracle-Gro Company Community Garden Campus also provides local residents with space to grow their own food and learn sustainable practices. Today, the conservatory balances its historic Victorian charm with modern commitments to local ecology and the Columbus community. **Maps of the Conservatory** Here is the [main map](https://www.fpconservatory.org/wp-content/uploads/2025/08/franklin-park-zones-scaled.jpg) of the Conservatory grounds. Here's a [map of the areas](https://www.fpconservatory.org/wp-content/uploads/2026/02/ConstructionMap-2026.jpg) in which the Conservatory has ongoing construction (see below). **Summary** For this event, we'll explore Columbus's highly-rated and very popular Conservatory. As mentioned above, the Conservatory is doing renovations on parts of the facility. These renovations are scheduled to be ongoing until the Fall of next year. Basically, no matter when you go to the Conservatory over the next 18 months, you're going to see some metaphorical orange barrels. So let's just go now. **Tickets and pricing** On the first Sunday of every month, the Conservatory is free for residents of Franklin County and the city of Columbus. You must bring an ID to receive this discount. (Yes, they do check.) Otherwise, tickets are $25.20. Members of the Columbus Zoo (of which I am one) do get a discount on tickets, though I have never actually bought a ticket to the Conservatory (I've always gone on free days). I believe the discount is $4. Parking is always free. If you have additional questions about pricing or whether and for what you qualify, you can reach the Conservatory at 614-715-8000. **Where we'll meet** We will meet just outside the main entrance. I guarantee there's going to be a line. The Conservatory is always popular on free days, and especially in nice weather. **Your GPS is stupid!** Be careful simply typing "Franklin Park Conservatory" in your GPS and going where it tells you. The only way to access the parking lot to the Conservatory is off of Broad Street. Unfortunately, since Google Maps is unable to find its way out of a wet paper bag, it has a tendency to want to take people to a mythical, non-existent Conservatory entrance on Nelson Road. If your GPS does this, just drive to the north side of the Conservatory along Broad Street. Your GPS should then redirect you to the main Conservatory entrance. If your GPS doesn't, then throw your phone away\* and look for the big Conservatory sign on the south side of Broad Street between Nelson Road and Franklin Park West. You also should be able to use the map pin I've provided, below, and it should properly direct you to where you need to drive. \* Don't really do this. **After the event** After stopping to smell the roses, for those that are interested, we'll head to the nearby [Columbus Brewing Company Beer Hall](https://columbusbrewing.com/location/beer-hall/) for [drinks](https://columbusbrewing.com/location/beer-hall/#draft-list) and [lunch](https://columbusbrewing.com/location/beer-hall/#food-menu). The Beer Hall's actual address is [200 Kelton Ave, Columbus, OH 43205](https://www.google.com/maps/place/200+Kelton+Ave,+Columbus,+OH+43205/data=!4m2!3m1!1s0x883889a94ac4acad:0xadb2e60240dbc38b?sa=X&ved=1t:242&ictx=111) (it's literally just on the south side of the Conservatory). Be sure this is where your GPS is taking you when you use it, as the Brewing Company has a taproom on Harrison Avenue that is *not* what you want for this event. We should be at the Beer Hall by 1 if you can't make the Conservatory and just want to join us for drinks.

Come out to Improving for our monthly iOS and Mac meetings. This Month's Presentation: Nothing yet. (You should volunteer). What is Cocoaheads (http://cocoaheads.org/)? CocoaHeads is a group devoted to discussion of Apple Computer's Cocoa Framework for programming on MacOS X and iOS (including the iPhone, iPad and Apple Watch). During monthly meetings, members present on their projects and offer tutorials on various programming topics. What is BuckeyeCocoa (http://buckeyecocoa.org/)? BuckeyeCocoa is a group of Objective-C/Swift developers/enthusiasts. We host monthly Cocoaheads and near-weekly NSCoder meetings in Columbus, Ohio. The meetings are free to attend. Presentations! Presenters welcome! We are always in need of people willing to present material. Any Swift and/or Objective-C related topic is welcome. Times can be 5 minutes (i.e. lightning talks) to a maximum of 2 hours. Interested? Contact info is on the BuckeyeCocoa website. To volunteer for a presentation contact us at @BuckeyeCocoa on Twitter. Follow us on Twitter! @BuckeyeCocoa (https://twitter.com/#!/Buckeyecocoa/) For more information: http://buckeyecocoa.org/

Bring your work or your hobby, hang out, and code with us. Follow @buckeyecocoa for more information.