We play this game in the raquetball courts at the YMCA, but it should work well in a gym. The soft nerf ball is first thrown against the wall by either the teacher or a student, and the ball has to bounce 3 times before anyone can touch it. After it bounces, its a free for all! The kids have to avoid being hit in the legs by the ball as other kids are hitting the ball with their hand trying to get others out. The rules are: 1. if the ball hits someone above the waist, it doesn't count 2. you can your hand ONLY to move the ball by hitting it (No kicking or throwing) 3. No double touching the ball (once you hit it, you have to wait until the ball hits something before touching it again.)and 4. If you are hit in the legs with the ball, you're out! This game works great with all ages. However, don't mesh the age groups, Kindergardeners should play with their age group, and 5th graders should play with their age groups. The older kids tend to get very competitive :) Have fun!