Sharpie Tye Dye Shirts- You'll need: sharpies (or other brand of permanent markers) and Rubbing Alcohol. Did this project in High School Chemistry Class!
Also on these boards
tie-dye tissue paper. From the comments: "A great permanent dye choice would be dye that one makes by placing the insides of spent markers in alcohol for a day or so. I also just saw a tutorial that uses water instead of alcohol, but don't think that would be as permanent."