Divide into two teams (or more if you have a lot of players. Choose one team to go first. Have someone watch the clock for 60 seconds. Have team 1 get into the pool. They can stand or sit. Say go! and throw 20 large ice cubes in and see who can take the most ice cubes out using only their feet in the designated time period. Then have the other teams try. The team who got the most out is the winner!