There are some great products on the market right now that help make bath time more fun. We have been using bath crayons for some time now, they allow your toddler to basically draw all over the bath and themselves and have a blast.
They are generally made of colored soap. They wash off very easily and make bath time a lot of fun.
Here is a link to our favourite product in this area.
Depending on the use they get, they generally last for 6 to 10 baths.