For all those on the East Coast, the "Drinking Skeptically" group for Connecticut is the best one I've been a part of. The organizer, Margey, is absolutely fantastic and has managed to book fascinating speakers every month ranging the gamut from Yale and NYU professors to local paranormal societies. We also take the occasional field trip on the weekend to places like the Natural History Museum in NYC. We have people come from all over Connecticut and New York at these meetings, so please come join us! 
http://skeptics.meetup.com/183/
http://skeptics.meetup.com/183/