Chelsea
Every minute on the minute for 30 minutes perform:
5 pull-ups
10 push-ups
15 squats
If you fall behind the clock, keep going for 30 minutes and see how many rounds you can complete.
If you've finished the workout before, this time add 1 rep to each exercise—i.e., 6 pull-ups, 11 push-ups, and 16 squats each minute—and see if you can go the full 30 minutes.