My daughter does not spend much time just coloring so all the great coloring books people buy us just sit around. I decided to try painting the coloring pages since my daughter loves painting. We had just bought neon paint to use under the black light and I figured that would make the project even more fun so I pulled it out (we use Creatology Neon Paint from Micheals). She picked out some My Little Pony coloring sheets (because we live and breathe My Little Ponies). We painted with the lights on but then taped the sheets up and switched to the black light.
Horrible picture but you can see how well they glow. She was super excited. We have decided to start painting more neon pictures to decorate the wall behind the black light table.
PS- This has been one of my favorite crafts from the last year. I might have got carried away and kept painting long after my daughter was done with the activity.