Soundbug

This British-designed innovation is about the size of a computer mouse and turns any hard surface into a speaker. Plug it into your music device, stick the sucker to a door, window or desk, hit play and prepare to be amazed when your surface of choice starts singing back at you. If you stick it to a window or door and then go outside the sound is equally as good on the other side. Its not going to burst your eardrums or throw out a dirty pumping bass but considering its diminutive size its certainly enough to keep you entertained if your on the move. Ideal for the nomad who likes to travel light - stick it to your hotel room mirror, window, wardrobe to enjoy your tunes.

Now for the science bit - the main component of the Soundbug is a tiny piece of a material called Terfenol-D, which was originally used by the US Navy for sonar work. The Terfenol is placed within an aluminium case and a coil wrapped round it. When electricity is passed through the coil the Terfenol expands slightly creating a massive force of 400 pounds - when its attached to a flat surface it transmits electronic signals into mechanical energy causing the flat surface to vibrate and broadcasts the sound.
If that's not enough to whet your appetite its even got a cool energy saving feature which turns it off whenever the music stops so it won't chew up your batteries.