To prepare for this game, you need two balloons for each person in your group (plus some spares for those that might break whilst you're inflating them). Preferably the balloons should be two different colours (to represent two different teams). Tie two foot long strings to the ends of each balloon.
Give each person two balloons (of the same color) and have them tie one to each leg. Separate the teams on either side of the room/area.
When you say start, the Kids try to pop the balloons from the other team by stepping on them. When both your balloons have popped, you're out and must sit down.
The team with the last balloon remaining wins.