For kids and anyone who wants to do a really fun and messy project.
Use finger painting paper because it doesn't wrinkle up with all of the goopy paint. It comes in a large tablet and has a glossy surface which prevents the paint from soaking in. Another option is old fashioned butcher paper. Paint on the waxy surface side of the paper. You can buy finger paint in multi- colored sets as pictured or you can make your own:
Finger Paint Recipes This link has lots of recipes for different kinds of homemade paint. All you have to do when you are finished is wash your hands and of course everything else within a 6 foot radius of the painting project. Yes, it's messy but it is sooooo fun!