Let the sun power your iPod

August 13, 2009 11:01 AM

UPDATED August 13, 2009 11:43 AM

More Videos

  • How much exercise do you need?

    If you turn on the TV, you're bound to see advertisements for a variety of exercise programs guaranteed to help you get in shape and improve your cardiovascular health. But how much exercise do you really need to be heart-healthy? And what type of exercise is best?