The Asus Pulse Sensing Mouse does just what it sounds like it does. It measures your pulse as you work away at your computer. Then it sends the information wirelessly to software running on your PC that keeps track of your heart rate.
It might be interesting to see what gets you stressed while on your computer. Heart patients would find it very useful. Other then that if you’re a hypochondriac, I guess you could monitor your heart rate while you surf porn. You know, just to make sure you don’t overdo it. Safety first.