A public domain PartyGame of suspicion, paranoia and bloody murder. One player is the Referee. Two players take the role of werewolves (or Mafia hitmen, or Thing-esque aliens, or Ninjas, or double agents, or Terminators or what-baddie-have-you) while the rest of the players take the part of the quiet townsfolk (citizens/astronauts/subjects/spies/resistance fighters/etc.) who are one gruesome killing away from becoming a vicious lynch mob. Roles are handed out in secret on slips of paper, or as standard playing cards with agreed-upon meanings, or expensively manufactured cards. Again, what-have-you.
Adding to the paranoia and mob frenzy, many (most?) variants have a Seer who can detect whether a given player is a werewolf during the nighttime phase. However, baldly stating you are the Seer is a good way of getting thrown to the wolves -- or to the lynch mob if they think you are lying in order to avoid being hanged. Thus, the Seer must find more subtle ways of convincing the mob of the guilt -- or innocence -- of another player.
Play proceeds thusly:
Variations abound. Some groups also like to have one player who is a defender. That player wakes during the night and chooses another player to protect. If the defender protects that night's victim, there is no killing that night. Other groups allow for one discussion and vote before the first night.
See also the Seattle Cosmic page for BANG!?.
I was fascinated by the game, first described to me as invented in France and called "Loupe-Garou" (I've learned since that the identical game 'Mafia' predates 'Werewolf'). I thought the lack of evidence would make the first rounds tedious, but the people I played with rose to the occasion, flinging accusations, making facts out of thin air, and hinging descisions on the slightest misstep or sound the referee made during the "night." It's fascinating to watch the werewolves trying not to cooperate during the day, and the seer's frustration at knowing who's evil but not saying anything that would tip off other werewolves as to her threatening identity. A superb parlour game.
When we play, we use playing cards to denote who's got what roles; red cards (mmm, blood) for the good guys, black cards for the evil people-eating whatevers. Some special roles we've used are:
The best site for Mafia/Werewolf rules is at The Graduate Mafia Brotherhood of Princeton.