Five stones

Paperdoll (spiffy website!) at The Heeren (not so spiffy website) sells these for $2. Five stones are about the easiest things you can sew, but $2 is pretty cheap for all that trouble.

A couple of years ago, at a class chalet, we were bitten by the nostalgia bug. So we got out old T-shirts, needles, rice, and almost-instantly whipped up a set of "stones" to play with. Boys against girls, suggested one of the boys. We didn't come from the same Primary School, so we had no idea how good (or bad) everyone else was. But everyone insisted they were the best, so we shrugged and agreed to split into teams along gender lines. Wait and see, everyone said.

A half hour in, and it was clear that the boys sucked. Embarrassingly so. While we were all nearing the 10-point mark, they'd just completed their first. Let's start over, we magnanimously suggested. We offered (and indeed, did) to play with our left hands, which probably didn't help soothe bruised egos, but no one protested.

The boys huffed and puffed, and they eventually managed. Well, they still lost, just by a more respectable scoreline. ;)

[Edit: You can find full instructions to the game here (complete with video!), although it must be said that the rules vary; there are so many permutations to play with. But as long as all the players agree on the rules, the game is on. :)]