Here is a game that can be played by any age level. Just make some small modifications appropriate for your grade level. The premise of the game is to have the fewest balls on your side when the whistle blows to end the game. So given that end goal, use lots of small soft balls with the younger age groups and with the older grades make it more skills appropriate. The example given here for older grades is to have the players serve a volleyball to get the ball to the other team's side. This sounds like a fun-filled fast-paced activity!