There are many situations in which you don’t want to fall asleep, for example, while driving or simply when you are sending IMs to your friend late at night…
The Wake-Up Angel monitors your head’s rotation. You have to set an angle (relative to the vertical axis) at which the device is going to vibrate. The angle can be changed so that you can read with a natural (inclined) pose.
The idea is fairly good, but I wish that the sleep monitoring was more high-tech than (I suspect) a mercury switch. Crave has a good point: this could be integrated in Bluetooth headphones to deliver a wake-up vibration and sound. I’ll try to get my buddy Randy to review it.