Body Bugg
It's a device that you strap on your arm...with an arm band...using the software and stuff it tells you whether or not...based on what you ate, your age, weight, and other parameters...whether or not you exercised enough. I saw one on a friend and it looked intriguing, but again the price tends to make me pause. I'm getting the impression not many people use them yet, which probably explains the price tag.
