"Light Sensitive Sound Boxes" are making the rounds on the intertubes as the best new way to vex your friends. The concept is simple: if the lights are off, the little box will start squawking. As soon as the lights go on, the sound stops, making it much harder for your mark to track the annoyance. $10.

The annoying sound box, which honestly needs a better name, comes in a few varieties. Crazy About Gadgets has the barking dog and the dripping faucet. Thumbs Up UK features a buzzing mosquito, and goes the extra distance, featuring sound samples and an annoying animated image to drive home the point.

Perfect For: Your house-mates' room; movie theaters; PowerPoint presentations in large corporate conference rooms.

Question raised: What other sounds should be added to the lineup? Screaming infants to drive new parents crazy? Dog whistles?

Check our Revenge Gifts for other ideas on sending the very worst.