A Rip-off on the classic computer game–
You need several three person slingshots** for this game, and ammunition that won’t kill people — like nerf balls, or soft cotton stuffed balls, but NOT LIKE TENNIS BALLS. (I don’t recommend water balloons for this game. You’d need several hundred.) Have about 10 rounds/team.
Using rope–or whatever–make two large circles (or more if you have more slingshots) and place your slingshot trio in the circle–this is your TANK. You may include two other team mates in the circle to act as your shield. All the rest of the team are ammunition gatherers.
The goal of each tank is to shoot and blow up the other tank. If they shoot a ball and it lands in the circle it counts for 50 points. If it actually hits the one of the three people comprising the tank’s slingshot/turret it counts for 200 points. If a shield or ammunition gatherer catches a ball out of the air it counts as 10 points. (The people on the turret can catch as well, but if they drop the ball it will count as 200 points for the other team.) First team to accumulate 500 points blows up the other tank(s).
** These slingshots can be made from surgical tubing. Simply make a large elastic band (5 feet in diameter) and sew a pouch in the middle (denim works well.) Two people stand and hold the elastic, acting as posts, and the third puts a ball in the pouch and pulls it back and releases it. Encourage the tanks to lob shots and not to B-line them.