Available today at Apple stores, Best Buy, and Target, the Jawbone UP is the latest addition to the trend of personal fitness tracking gadgets. The UP is meant to be worn 24/7. It keeps track of your movements during the day and your sleep patterns at night. It plugs into your iPhone to help you analyze that information. And it is smart enough to remind you to get up from your desk and move around if you've been sitting too long, and it wakes you at the ideal time in your sleep cycle.