Again with the ThinkGeek Foo?

$25 seems pretty steep for such a simple little doohickey (battery not included? Yeesh!), but oh the joy torment it will bring. It's the Mind Molester, and it emits a quick little beep every three minutes.

From the ThinkGeek's mouth:

The Mind Molester is an instrument of creative electronic harassment. ... Your friends/enemies will become obsessed, awaiting the next chirp trying to determine its location, completely disrupting their normal activities.

Just connect this device to a 9-volt battery and plant it in an appropriate location. It produces a one-second electronic chirp about once every 3 minutes. Due to the chirp's duration, frequency, and sound characteristics, it's a very difficult, time-consuming, frustrating and maddening task to locate the unit. And even if they find it, they'll have no idea what it is.