http://itunes.apple.com/us/app/bang!-the-official-video-game/id406634232?mt=8 This was originally a board/card game. From wiki: "In 2004, Bang! won the Origins Award for Best Traditional Card Game of 2003 and Best Graphic Design of a Card Game or Expansion." It's a pretty fun game, though a bit simple graphically. Haven't tried out the multiplayer, but single player is still kinda fun!
