I checked Instructables for some news because I haven't checked it for about 1 month now, and I saw this little contest. So I said " why not ?" . And the first thing that came in my mind was this glow stick. It's simple, and in a time lapse ( be sure to pause the video from time to time, I speak reaaaally fast :D ) it can teach you how to do it. It's DIY fun !
Have a nice time.