My friends and I play The Resistance (http://boardgamegeek.com/boardgame/41114/the-resistance http://boardgamegeek.com/boardgame/41114/the-resistance), which is

My friends and I play The Resistance (http://boardgamegeek.com/boardgame/41114/the-resistance http://boardgamegeek.com/boardgame/41114/the-resistance), which is along the same lines, with some traitors secretly mixed into the rest of the group. The difference is, unlike in Werewolf (or Mafia), nobody gets eliminated, so nobody has to sit out for virtually the entire game.