For those of you into sound synthesizers, you might want to take a look at this video where the creator uses aluminum foil and conductive foam to make pressure sensing sound synthesizer to make some cool sound effects. (on YouTube)
A first test of a simple DIY pressure sensor surface for controlling analog synthesis. It is built from cheap conductive foam, with aluminium foil taped on both sides in various patches. Only the right side of the sensor surface is connected.