Music helps the weary exerciser work harder and, according to a hacker named Steve, the louder the music the more vigorously you work. So, he grabbed a motion sensor and an DIY MP3 player
, stuffed them both into a disused French Vanilla Cafe coffehouse beverage drink container (ooh, la la), then wired the works together to pump out the jams louder when you're really burning those calories -- or to get quieter when you stop for a breather. It's all fearlessly demonstrated in a video after the break featuring Steve, a jump rope, and a little bit of Bono. Make sure you stay through the credits for a deleted scene!