Godzilla: Save the earth
I wouldn't recommend it as a singleplayer game but if you have friends over, there can be up to 4 players.
The game is pretty much this: choose a monster and beat the other monster(s) up, while destroying the city in the process.
fun stuff like being able to swing a building like a baseball bat or stubbing a monsters toe make it great, and when its 4 players on one screen trying to figure what the forget is going on its a great time.