Place two teams on opposite sides of a large field, each with a flat, mid-sized target and a “Shoot From Here” line. The target can either be propped up or laying flat. Give each team a water balloon launcher and a supply of water balloons. Each team is trying to hit the other’s target by launching the water balloons. Have the teams rotate personnel on the launcher with each attempt. Go until the predetermined hit limit is reached.
It is possible to play this with more than two teams, but you have to have enough space to make it challenging for the teams.