Another great idea from Family Fun magazine: Drop several drops of food coloring (multiple colors) on a sturdy, rimmed paper plate and send your kids out into the rain (works best when there is a light shower). The colors will splatter and blend, leaving your child with a beautiful work of art, a lesson in color mixing, and a bit of fun on a rainy day.

Learn How Rainbows Can Change The World!
http://www.gurupal.com/rainbows.html