Once a month we get together. Sometimes we write code together; sometimes one of us volunteers to share experiences with the group.
The coding exercises, or katas, are performed by pairs of developers using test-driven development. The exercises are language agnostic; historically common choices are Ruby, C#, Java, C++, Object Pascal, Erlang, F#. If you want to improve your skill in one of these, or want to introduce a new one, you'll find someone who wants to sit down and tackle a problem with you.
Some of our members have given talks a large conferences and have a lot of knowledge and experience to share; our stage has served as a test track while they tune their presentations. Other times, we have yielded the floor to significantly more junior coders to gain insight from their valuable perspective. We've also had members facilitate round-table/town-hall style discussions. If you have a topic you'd like to bring to the group, let us know.