You'll need:

Paper cups (not plastic or styrofoam!)
Candle-making wax
Candle wicks
Glasses (old jam or honey jars also work)
Old crayons, cut into pieces, separated by color
Popsicle sticks (or something similar for stirring)

Here's how:

1. First put a little bit of wax in one of the paper cups and melt it in the microwave. Place a wick into one of the clean glasses and pour the wax in so that the wick sticks to the bottom of the glass. Leave it a moment to dry.

2. Now liquefy more of the wax and add the pieces of one your crayons. Don't forget to remove the paper on the crayon!

3. Use a popsicle stick to stir the wax and crayon around as they melt so that you just have one well-mixed color at the end. Now pour this mix into the prepared glass.

4. As soon as this layer of wax has hardened, start again with another bit of candle wax, adding the next crayon and then melting and stirring them together. Now pour this color on top of the first.