PRS 25 is rock-paper-scissors with 25 different gestures, also known as rock, paper, scissors, gun, dynamite, nuke, devil, laser, alien, moon, snake, sponge, cardboard, spoon, candle, dragon, geekologie writer, bowl, water, magic, dagger, tank, air, something, nachos, leopard, something, etc.. If 25 gestures is too many for you, there is also standard rock-paper-scissors and 5, 7, 9, 11, and 15 gesture varieties (and a mind-boggling 101-gesture version HERE). I like some of the explanations for why one particular sign beats another. Like, "Rock crushes woman", "Monkey flings poop at woman", and "Woman has sex with dragon". Okay, I made that last one up, but I did see it in a movie once. And that movie, my friends, was Harry Potter.
Thanks SomeGeek, you beat me again.