Those crazy cats at PhotoExtremist have put together this rather involved tutorial on how to make light paintings using steel wool. If you don’t want to watch all 8 minutes of the video, here’s the short version: put fine steel wool inside of a whisk. Attach a cable to the handle. Ignite, and spin it all over the place.
But if you’re going to do this, please, please be careful. You’re shooting embers in all directions, which makes it very easy to burn yourself, and set things on fire. Protect your eyes and skin, and make sure you have a fire extinguisher on hand in case you ignite your surroundings.
The results are pretty astonishing, and far more dynamic than what you’d see using a flashlight or other light source — the sparks flying in all directions really make the shots.