This is certainly not an original idea. I have seen the idea of making your own crayons a bunch of times over the years. It has always been one of those project ~ See more about party favors, homemade crayons and crayons.
instructions: Cut out a circle from construction paper. Pour a little oil in a bowl. Have the child dip their q-tip and draw a design on the circle. Hang the design in a window and watch it glow in the light.