This combination ball toss and optical illusion is a great warm-up game suitable for anyone who feels comfortable throwing and catching a ball.

WHAT YOU'LL NEED: At least five players and three or four soft, midsize balls.

RULES: Begin by having players stand in a close circle. Take one ball and toss it across the circle, from player to player, until each person has caught and thrown the ball once. After your pattern of tossing and catching is established, repeat it several times, until each player knows to whom she tosses the ball and who will be tossing to her. To help everyone remember the pattern, you might have players call out names as they throw. Once everyone is comfortable with the sequence, add another ball to the circle, following the same pattern. Then, try adding a third and a fourth ball. You will find that the visual effect is striking: Because the four balls are being tossed and caught almost constantly, it will look like your group has achieved a huge, complicated juggling maneuver.