Most people have heard of this game. You simple tie a balloon to each players left ankle (we used red balloons for the "red team," and blue for the "blue team" when we played) and put them in some sort of a boundary (circle or square) that was small enough to crowd everyone a bit.
When the dierector says "go" (or "stomp," or whatever), each player tries to stomp on the other teams' feet...er...balloon until only their team's balloons are left. Obviously, the remaining team is the winning team. This game is a lot of fun, but be prepared for some sore toes and ankles!