Eating, surfin' the web or emailing friends. See who's lurking behind you before they surprise (and startle!) you with a computer rearview mirror attached to the top right or left corner of your monitor. Sold as a set of two - one for your work computer and the other for home! (#9132) A ComputerGear exclusive.
I got two of these a few years ago as SWAG while at a Telecom convention.
They came with some sticky pads and the backs are cut so they fit perfectly on the corners of your monitor. At least they do on the CRT monitors we have at my work.
Rearview Mirror (set of 2)