They turned out SUPER cool!
I'm not sure if the kids really appreciated the tie-dyed cupcakes (as Adam referred to them as) as much as I'd hoped, but the icing was thoroughly enjoyed - that's for sure!
They were SO easy to make. I used a yellow box cake and a can of cream cheese frosting. Follow the directions on the box, and evenly divide the cake into four individual bowls for food coloring. I put a spoonful of each colorful batter in the cupcake liner, just one on top of the other, and baked as directed.
Side note: I used the new snack size box of yellow cake mix that makes 12 cupcakes instead of 24. I LOVE this! When I make cupcakes, I always want to make just 12 because my cupcake carrier only holds 12. The new snack boxes are awesome!