The Nike Fuel band is a pretty neat looking blend of technologies. It’s got an accelerometer that collects data on your movement through the day, then uses that data to measure your activity: calories burned, activity level and so forth. It all syncs with software or an iPhone so that you can track long term trends. An array of leds on the wristband light up as you work your way through the day, letting you know how much of your goal you’ve achieved.
It sort of turns your daily activity into a social video game.