- Water balloons; make a lot before the game begins so there's not a break in the action
- Baseball bat or whiffle-ball bat
- Enough outdoor space for setting up the playing field
1. Divide players into two teams and take turns batting and fielding as usual. Rather than calling strikes, you may want to change batters after a certain number of swings, and switch places whenever all the players on the at-bat team have had a turn at the plate.
2. Give each team a point for every balloon they break.
3. The outfielders won't have much to field, but they can try to tag the runners before they get to base.