Let your children paint to their hearts’ content – the paint washes right off.

Materials:
Fluorescent or Neon paint
Shaving cream
Silicon muffin pan

Directions:
First squirt the shaving cream in the muffin cups.
Second add some paint (it doesn’t take much)
Use a plastic spoon to mix.
Glow fun in the bath tub with glowing paint!

Source: mycrazyblessedlife.com/2014/03/31/glow-bath-paint/
Check out the other 65 Days of Summer Fun ideas here.