Mix cakes according to package directions.
Divide batter between six bowls and color using food coloring- purple, blue, green, yellow, orange, red
Pour each color into a pie plate that has been sprayed with non-stick spray and bake in a 350 degree oven until toothpick inserted in center comes out clean.
Remove cakes from pie plates and allow to cool.
Using your Ball Jar lid or cookie cutter, cut 4 circles from each color cake.
Assemble colors in order putting a layer of Cool Whip between each color. Stick a sucker stick down the center to help the stack stay straight and ice the outside with Cool Whip!
Sprinkle with rainbow sprinkles till your heart desires!