re: Umm... you missed those, I take it?
I checked into Mensa once and got to meet some of the members. They were a pretty nerdy group and seemed full of themselves. The honor wasn't worth hanging out with boring people.
It was interesting but my first experience with an atheist organization was much the same. The group was all fat. Most smoked excessively. Their major activity in life was pontificating all the time. Recently I've met some more interesting and well-rounded atheists although it's tough to meet regularly in this huge valley without traveling way too many miles.
Generally though I adhere to the W.C. Fields (I think it was him) saying, "I wouldn't want to be part of any group that would have me as a member."