The ThinkGeek Annoy-a-tron

The ThinkGeek Annoy-a-tron ($10) is a simple electronic gadget used for annoying unsuspecting victims. Once turned on, it will emit a short, annoying beep ranging between 2 kHz and 12 kHz every 2 to 8 minutes. Turn it on, hide it, and let the fun begin as you watch your friend/coworker/family member desperately try and find this annoying noise maker. It is very tiny so the culprit can get creative by hiding it in hard to find places. Beware: The device will likely be returned to you smashed by the victim.