Belly Flop Contests
A belly flop contest is a great impromptu game, especially if you have a group of kids (or grown-ups) who are more interested in laughing and goofing off than focusing on a game with rules and structure. You'll need a judge and a set of parameters for determining the winner. Criteria can include form, height or length of jump and how much pain they're in when they get out of the water. He with the reddest belly wins.