I recently found out how to "paint with light" and have fallen in love with it ever since. The two shots in this post were made by steel wool and a long exposure.
Things you will need:
1. steel wool
2. a whisk ( pick up one from the dollar store)
3. cable or string
4. camera and tripod
5. dark clothes
6. flash light
7. a friend
Start out picking a location that is fairly dark. Pull the steel wool apart and stuff the whisk with the pieces. The more the wool is pulled apart the more sparks will be thrown into the air. Attach the whisk to your line and practice spinning it in the air. I say practice because the first few times I tried this we came extremely close to hitting our face with the flaming whisk... not good haha. Set up your camera on the tripod and set it to shutter priority mode. Usually a shutter of speed of 10 to 15 seconds is plenty. Use the flash light to shine on your friend standing in the frame so that you can manually focus on him/her. Light the steel wool with a lighter and let your creativity flow. Circles always look cool but try other things like banging the whisk on the ground as you spin it. BE CAREFUL!! Sparks go flying everywhere.
Look me up on facebook at Flat Land Photography to see some more of this.