I did this rainbow craft with Lizzie and Bryce a few days ago. It was simple and the kids really liked it! All that I did was cut different colors of craft foam (or you could use construction paper) into little squares. I drew a simple outline of a rainbow on a piece of blue construction paper. The kids glued on the craft foam according to the colors of the rainbow. Then they glued cotton balls on the bottom to form the clouds. Easy!