Now I know what your thinking after reading the title to this post, "what, that doesn't sound like much fun," but seriously it is the easiest, mess free kids craft ever!! And.....the kids love it! They can paint and paint and paint and never run out of supplies! Plus I guess it's kind of like a science lesson as well since you are explaining how the water is evaporating and their picture will soon be invisible! When I taught preschool this was always a big hit with the kids, plus it's defiantly something new so they are completely fascinated by it.
Bucket of Water, various paint brushes, and that's it!
note: this really works best on concrete but it could work on a lighter shade of pavement.
You can also paint your pacifier....
...and the dog:)