Spotted in the MAKE Flickr pool:

Flickr user zachaholic built this VU toaster, using a sound volume meter to directly control the heat of the toaster. To release the toast, you simply bang on the cymbal next to it.

I could see a cute extension to this, where you have to choose the pair the right kind of music with each toast- soft music for delicate breads, and heavy metal for crispy bagels. In addition to just being a funny idea, it would also let experiment with varying the temperature applied to the toast over time, to see if that has any effect on the outcome. You could even extend the idea to a reflow oven for doing surface mount soldering in style!