I recently learned about an awesome Dr. Seuss-inspired field day planned and organized by Patti, an elementary school PE teacher. Here is one of her 21 stations:

Station 19

Title: Hop on Pop

Skills: gross motor, balance

Description: Divide students into 6 equal teams with the first person from each team sitting on a hoppity hop ball. On the signal to begin, these players hop on the balls around the cone and back to the start. The next person in the starting hoop will sit on the ball and wait for the next signal to begin. This is an individual race, not a team relay. These races should continue until time has been called.