Drive your co-workers nuts by hiding the Annoy-A-Tron somewhere in the workplace. The Annoy-A-Tron will emit a beep at maddeningly long intervals, from 2 to eight minutes apart, making it difficult to find the source of the noise. When they find it, they still won’t know what it is! Link -via the Presurfer
On second thought, don't. Or at least don't tell anybody where you got the idea.