I saw this pen in action a few years ago and it is pretty slick. It was being used by a handicapped girl whose father worked for Compaq (the pen was actually branded with the Compaq name). Anyway, it was useful because if someone needed to get a hold of her while she was in class, she could leave the phone in her purse, be writing with the pen, and know her phone was ringing.

However, if you are close to someone else with a cell phone, it will flash as well. Still, it's a pretty cool toy.