You can volunteer to present or come to listen. Each presenter gets 5 minutes to tell us about a thing they've made (software/robots/etc); then the audience gets 5 minutes to ask questions.
After the meetup, people trickle out. If there wasn't time to ask your question during the 5 minute window, you can catch the speaker then.
If you're willing to speak, please either post in the comments here or email me at tmurray at wumpus-cave dot net. New speakers are always welcome, and the audience is friendly.
[We expect that if you're presenting a software project, you can show us the code. (This isn't a place to advertise your company's product, for example.) Unfinished/unpolished projects are welcome, but not presentations that are just ideas or plans.]