Give each team a plastic cup and a bucket full of water. Put one empty bucket for each team at the finish line. Players must take turns filling up their cup from their bucket, then dumping it into their empty bucket. The game is over when the once-full bucket is empty; the team with the most amount of water in their finish-line bucket wins.
Variations: Use a large sponge instead of a cup; poke a few holes in the cup and make kids carry it over their heads.