Many people have the problem of standing a bit too wide when asked to stand with their feet hip-width apart. A FitSugar blog post explains how to find this stance naturally:
March slowly in place, stop, and then casually kick up your left leg and allow it to fall back to the ground naturally....
Jumping rope intensely for 10 minutes has about the same calorie burn as jogging for 30 minutes.
Ever have one too many cups of coffee and get the jitters? Try doing a quick set of 15 pushups. It helps channel all that extra nervous energy and then you're not so jumpy!