There is also PongClock Live Wallpaper. Classic game of pong, where you can watch simply, or join the game at any time. It also lets you manipulate a variety of settings.
I also like Striker Live Wallpaper. Its for soccer fans, but it has a few players kicking a soccer ball around the field. Tapping the screen anywhere, kicks the ball to that spot, while the players chase it down and continue playing.