It seems to me the only reason to join MENSA is to brag about the fact that you got in.
http://video.google.com/videoplay?docid=3164300309410618119#...
If you're looking to meet interesting and intelligent people, you're probably better off finding a community oriented website with content that appeals to you and going to meet ups. Personally I would much prefer an HN meetup to a MENSA gathering.
http://www.mensa.org//loginaction.php?action=error&acc=1... the new Mensa, now XSS compatible!')</script>
I sent them an email, let's see how long they take to fix it.