If you are bored one day and decide it’s time to anoy someone then go pick up an Annoy-A-Tron. It’s a small circuit board with a battery on it and it’s designed to make your friends or office workers get annoyed. The circuit board can be planted anywhere with it being very small in size. An example would be under a desk. It then emmits a noise from 2KHz to 12KHz from time to time which could really drive the boss up the wall.
Via: OhGizmo
This looks like a fun way to annoy your friends.