Come out to the OpenStreetMap 2014 spring #editathon in Washington DC. Editathons are held quarterly all over the US (http://openstreetmap.us/2013/07/why-editathons/). Mappers of all skill levels will be present, so if you’ve never edited OpenStreetMap (http://openstreetmap.org/) before this will be a great opportunity to learn how to. If you’re an experienced contributor, come out to connect with others and push on your favorite mapping activity.
The #editathon is not limited to an indoor activity. If you'd plan to go out and survey, meet up with other likeminded people at the #editathon venue and head out for some open air mapping.
The event will take place at the Mapbox DC office, on 1714th Street NW, Rear Entrance. This last bit is important, it means you need to walk through the back alley, you can't enter from the 14th Street side.