The first step toward getting in shape is always taking an inventory of your fitness and eating habits, and a handy gadget dubbed the Fitbit makes it easier. A small digital sensor that you attach anywhere on your person, Fitbit keeps a rough inventory of your physical activity during the day, the calories you've burned, and even your sleep patterns. The device is supplemented by a website that lets you log your meals to track calorie consumption for the day. Is it perfect? No. The Fitbit won't be able to accurately measure your calories burned with more intensive activities like weight lifting or biking it works best for walkers or runners. But if nothing else, the Fitbit is a digital gadfly to hold you accountable. (Fitbit, $99)