Circuit bending is the art (as opposed to science) of modifying audio toys to produce musical instruments. By creatively shorting circuits, adding switches and pots you can create a truly unique musical object. The hobby is incredibly easy get started in; just roll down to your local thrift store and pick up some old speak ‘n’ spells and start poking around. This comes with all the usual disclamers i.e. don’t hook house current up to your body. If you’re careful though you’ll soon be hearing the wonderful sounds of a know-it-all speak ‘n’ spell in agonizing pain. Sound like fun? Have a look at Anti-Theory’s great guide to everything you need to know to get started with circuit bending.
There is also an interesting gallery show over at Crown Dozen.