I came across a really cool video by Michael T. Bullock (via Keri Smith). I love the idea of drawing using the vibrations coming through speakers.
Michael explains :
In “Speaking Drawing,” a series of watercolor paper cards and 2"x3" art boards are placed in a large loudspeaker lying on its back on the floor. A very low, slowly changing tone is played through the speaker, causing the objects to bounce and shimmy around inside. I then drip India ink on the papers and blocks and attempt to draw on them as they quiver uncontrollably.