Homemade bath crayons - Buy some glycerin soap at a craft store. Melt it in the microwave, add food coloring, and pour into a mold. I used an ice cube tray. Takes about an hour to cool completely, then pop out of the mold and you have crayons!
bath time fun - colored ice cubes - This is a simple way to add a little (more) excitement to the bath time routine. - They love chasing the colors around while they melt. Colored Ice cubes for Bath time fun
this one sounds even easier to make: bubble snakes = easy quick craft. Cut the bottom off water bottle. Put old sock over bottom and duct tape. Add food coloring for fun. Dip end in dish soap mixed with a little water