KarBOOM is a fast-paced local multiplayer car-combat game for Windows, Linux and Mac. Knock other players out the ring, chase the flag, play kar football, and bet on how long you can survive with everyone hunting you! Play in teams or every kar for itself!
Coming up in the next update is support for ridiculous amounts of players. This is still offline only (so get ready to bust out them gamepads!), but is a big step towards online play.