Good question.  I think what to expect... highly depends upon the makeup of the group.  My group is lucky enough that we have a house that is owned or rented by the group (I don't ask).  The house has been turned into a hacker's lodge of sort.  We get together, listen to presentations, drink, and BBQ.  That is the general monthly get together.  Members go there other times during the week when they want a quiet place to work (it's wired up as you might imagine).  Or do whatever.  We have a nice server setup, sodering area with grinders and lots of fun stuff/tools.  I really think you'll find different setups and whatnot with each DC group.  This is the only one I've hung out with in person, but... Noid is our leader... and he's been the head of the Defcon goons forever.  Hell, Jeff Moss joins our group once in a while since he lives here.  I think I'm pretty lucky in my situation.  There are lots of other non-DC groups out there as well though.  The Seattle wireless group is pretty big.  There are a number of groups that just meet online too.  IRC... etc.. SILC.. whatnot.  Just get your feelers out there, do some googling in your area, and see what you can find.