I went to a couple of meetings with a friend when I was in my teens. (For obvious reasons, I was never asked to join.)

Membership in Mensa is open to persons who have attained a score within the upper two percent of the general population on an approved intelligence test that has been properly administered and supervised. There is no other qualification or disqualification for membership eligibility.
http://www.mensa.org/index0.php?page=10

My impression is that this qroup consisted of a bunch of bright albeit VERY socially awkward kids whose parents wanted them to go to the meeetings since they felt and acted "different" from the general teen populace. I guess the parents wanted them to know that there were other people around like them.

There was a sort of oneupsmanship going on - who could talk the smartest.

From an appearance viewpoint, it sort of looked like the bar scene in the first Star Wars movie, except without the intoxicating drinks or music.

As I'm writing this, and although I've never been to a GTG, I am thinking that half of the membership of this forum might qualify....







At least if the intelligence test qualification part was removed.