As students enter the activity area ask them to get a balloon (have them all the same color if you think your kids will fight over them) and then find a good self space in the general space (marked off by cones).

On the teachers signal allow them to strike the ball towards the ceiling in their own space using as many different body parts as they want (elbow, head, knee, wrist, shoulder, etc.). (Only body part to discourage may be the foot as the kicking motion may be dangerous and it is tough to get the balloon to the ceiling.) Tell them their goal is to hit it up in such a manner that they shouldn't have to move from their own self space. Have them do this for 3-5 minutes. Have them put equipment back and come to you to move on with the days lesson.