The Fitbit accurately tracks your calories burned, steps taken, distance traveled and sleep quality. The Fitbit contains a 3D motion sensor like the one found in the Nintendo Wii. The Fitbit tracks your motion in three dimensions and converts this into useful information about your daily activities.

You can wear the Fitbit on your waist, in your pocket or on undergarments. At night, you can wear the Fitbit clipped to the included wristband in order to track your sleep. Anytime you walk by the included wireless base station, data from your Fitbit is silently uploaded in the background to Fitbit.com

More info: fitbit.com