The one I go to (Gender Mosaic in Ottawa, Canada) has a monthly pot-luck. You show up, bring a food item, and just socialize. Sometimes they'll have speakers on various topics, and there's usually about 20-30 minutes of official business (announcements and the like.) But mostly it's just to eat together and talk.
They also organize a monthly restaurant outing. This is to help people feel comfortable going out in the "real world". They pick from a pool of 20-30 restaurants that have been vetted as T-friendly and we just go out, eat dinner and have fun.