There is a party game called Mafia (or Werewolves or sometimes other things) that is also played online in forums. I just recently started playing it, and enjoy it a lot. It combines logic and analysis, and is usually a lot of un.
A cool site for learning the basics of the Mafia game, it includes roles and how to play. The links take you to Mafiascum.net, but I like playing at Paranoia Paradise.
I mostly play here: