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Bonus 2: As we all know, ThinkGeek makes some pretty awesome gadgets. Well, as it happens, they make one nifty prank gadget that's sure to frustrate anyone you choose to make your victim. It forces random keystrokes, sporadic mouse movements, and toggles the caps lock key at random times. You can read more about it here, but being the owner of one, I can vouch for the side-splitting laughter it induces!
[Related Gallery: 20 of the coolest gadgets and must-haves for your office!]