One day my boys spilled way too much syrup on themselves at breakfast and needed a mid-morning bath (we usually do baths at night). I knew my 6 year-old might object, so I made it a little more enticing by telling them they could paint in the tub. We just mixed up some (cheap) shaving cream and food coloring to make the "paint." My boys loved helping with the mixing process!
They happily hopped in the tub and all three painted to their heart's delight. It washed off the walls super easily, too. It also became an inadvertent color mixing lessson, because they found that their yellow and blue paint turned the water green! This was a fun and easy activity that we will definitely be doing again - I need to stock up on shaving cream at the Dollar Tree!