Last week I was introduced to a pretty solid workout that involved both a track and a field. The first 25 minutes were a mixture of pushups, crunches, jumping jacks, squats and leg lifts. I think you can substitute in just about any exercise that you like here - I wasn't overly impressed with our routine. However, I did think the next 25 minutes were a pretty interesting workout.
The first leg of the exercise was a lap around the track. You choose your pace. Once you have completed the lap, you immediately get down and do 10 burpees, 10 star jumps and 20 mountain climbers (this takes less than a minute generally). Then, you get up and run another lap - again at your own pace. After every lap you do the same exercises - burpees, star jumps and mountain climbers. Believe me, they get pretty hard by the end.
It depends completely on your pace and what kind of shape your in, but make your goal to be running 3 miles. This means you will complete 12 laps around the track, which in turn means 12 sets of burpees, star jumps and mountain climbers. Your legs may be quite soar the next morning.
Until next week, good luck.