For several months every year, our Seattle skies are filled with gray clouds. So as a kindergarten teacher, I was always on the lookout for easy, rainy day activities that would make inevitable indoor recesses fun for my students. Hands down, Monster Mash Up was one of the kids' all-time favorite projects. Now that I have children of my own, I can officially declare this simple activity a winner. It's guaranteed entertainment at doctors' offices, restaurants, and on airplanes.