Create two parallel rows/lines of spots (blue/red/yellow/green) and have students pair up facing each other standing on their spot. Each pair will recieve a tennis ball and will throw back and fourth to each other. Every time the ball is caught, the person that caught it will take one big step away from their spot (starting point). Every time the tennis ball is dropped, the player that dropped it must take one big step closer to their spot (stat point).
Use a larger or smaller ball to change the difficulty of the activity. Place students into groups of 3 or 4 if there isn't enough equipment available.