Four months ago I attended a Drupal users group and I was underwhelmed since the group was mainly web developers, not programmers. So of course I found myself at a Ruby users group (so close that Wlofie and I walked there).
I went not because I'm terribly interested in Ruby (although getting a feel for the language certainly won't hurt) but because an old friend from college, Steve Smith had organized the meeting and I thought it might be nice to drop in and say hello.
It turned out that this group was more aligned with my interests than the Drupal users group. The first presentation was on distributed Ruby, which had a unique feature—if the local side could not marshall an object to send to the remote side, it basically signaled the other side to make a remote call back to do the actual processing, so neither side could really claim to be the client nor the server—both sides could act the role. It's a bit baroque for my tastes, but still, an interesting solution to a problem with remote procedure calls.
The second presentation wasn't a presentation as it was a discussion on design patterns in Ruby, which lead to a digression through the source code for Rails 3.0 and a few coding techniques that several of the more knowledgeable Ruby programmers in the room didn't realize were possible in Ruby (and a whole new way to write ravioli code—wow).
And oddly enough, they were interested in some of the projects I've done in Lua. So it's definitely a users group I can see going to again.