I found a new toy today. Crayola has a new product called "Wild Notes" it is basically a spiral notebook that comes with a special pen. When you write/doodle on the paper with the pen the lines are multi-colored (green, red, blue, purple, pink, orange). The colors are really intense when you shade in sections of your doodle.
The pen does not work on regular paper and using a regular pen or pencil in the notebook does not produce color--you have to use the Wild Notes pen and paper together to get the effect.
Here is a link to product information on the Crayola site:
http://www.crayola.com/products/splash/wild-notes/
WOW! I wish this had been available when I was in school--but then again, I probably would have doodle in class even more than I did.