Candy Rainbow Cupcakes

Rainbow Cupcakes from Cupcake Mania

If you are looking for a fun and easy way to make some rainbow cupcakes, candy might be the way to go.   Cupcake Mania used Airhead Extremes.

Living Lucruto used gummy worms:

And I didn't find them in cupcake form, but Nerds would be fun too.  Not three dimensional, but fun.  Like this image is from Pink Sherbet Photography.