Soap Crayons 

Stir hot water into the soap flakes.

Spoon some of the mixture into an old margarine container and add a few drops of food coloring until it's the color you like.

Fill ice cube tray with soap and put in a warm breezy place to dry -- takes 48 hours to one week.

Take out of mold and let dry for another week before using.

Use crayons to draw on the side of the bathtub during bathtime.