Sometimes it's a little difficult to find a way to burn off the energy that a 3 year old has.  I don't know where it comes from, but I'm sure that if we could somehow tap into that energy, our energy crisis would be taken care of.  Zach wanted to do a race, so using a microwave timer, I had him do hot laps.  He kept saying again, and again.  This went on for 20 minutes.