My fifth grade teacher used to play this game with us in P.E.. It is sort of like dodgeball, only more fun.

Set Up:
The game is played out on a squarish/rectangular court. Sidewalk Chalk is advisable for setting up boundaries if no ready-made courts are present. Get a group of people and divide yourselves up into two teams (in our class it was always girls against boys, hmm..) Once you've decided where you want your court to be, designate a dividing line down the middle. Each team stays on their side of the line. The area behind each team's side of the court is where the "Jails"/"Prisons" are. Set one or more rubber balls on the dividing line between the two teams.

How to Play:
At the signal (any signal, make one up) people on both teams run forward to grab the balls, and throw them at people on the opposite team. For a hit to count, the ball can't have bounced on the ground more than one time. Once you're hit, you're out and you must go to the jail that is behind your opposing team. If you catch the ball however, the person who threw it at you must go to jail. Players are not allowed to leave their side of the court, or else they go to jail too. The last team left with members free of incarceration is the winner.

Fret not! You still have (minimal) power even while in captivity. If any of the flying balls get past your rival team and make it into your jail space, you can pick them up and chuck them at your oppressors. If you hit any of them, you are free once more.

The rules are, of course, bendable according to taste. Sometimes there are no restrictions about the # of bounces allowed. Sometimes people play without jails at all, instead simply disqualifying players who get hit. Whatever floats your boat..

But note: The more balls you play with; the harder and crazier it is. And the more challenging; the more fun. I recommend a ratio of at least 1:5 balls to people.