I know lots but I'm going to put on 2 Bloody Knuckles, where your suppose to scrape your knuckles on a piece of wood until they bleed. And Red Rover I know its not really suppose to hurt but if your short you can get clotheslined alot, I've seen it.
Mercy, where you interwieve your hand with someone elses, and both players attempt to bend back the others hands until he crys out in pain.
And my personal favorite, Sting. Where you use your hand as a whipe, and attempt to just flick someone in the genitals. In public places. If you cry out, you lose. If you get caught, you lose. Its like the P*nis game, but with pain.
I play quarters. (Not the drinking version). You take a quarter and your opponent puts there fist down on the table and you slide at their fist as fast as possible and the first person to bleed loses.