Official Rules: Slap Cup

1. Setup. About twenty cups in the center, each a third full. Two players on opposite sides each take an empty cup and a ball.
2. Shoot. Bounce the ball off the table into your own cup. Keep shooting until it goes in.
3. Pass. Make it, then pass cup and ball to your left. Make it first try, and pass to anyone.
4. Slap. Make it while the player on your left is still shooting, and slap their cup off the table. One point.
5. Slapped? Take a center cup, finish it, and keep shooting with it.
6. Slap the cup, not the player.
7. Center cups gone? Game over. Most slaps wins. The last player slapped racks the next game.

Stacking instead of slapping? That's Rage Cage.