Here's a reusable alternative to a summer favorite, the water balloon: colorful, multi-tentacled sponge balls.
For each ball, you'll need 3 plain kitchen sponges fresh from the package and still slightly damp. Use scissors to cut each sponge lengthwise into 5 strips about a half-inch wide. Stack the strips as shown.
Loop a piece of strong string around the center of the stack and pull tightly. Double-knot the string and trim the excess.
For a fast cool-off game, have two players stand a few feet apart, each beside a bucket of water. See how many times they can toss the ball back and forth, taking a step apart and dunking the ball in a bucket before each throw.