I don't think you should list them unless you are active in some capacity like on a board, running some activities like a SIG group on a regular basis, etc. I don't think it shows a thing about collaboration; I am in Mensa, and I can tell you that some people I have met there would be good collaborators, and some would be awful -- it doesn't mean anything about your collaboration ability to be a member. You really can't offset a poor GRE score with these memberships, IMHO.