A spectator places a die with 6 different colored spots on it into an opaque box, with any freely selected color on top, covers it with a lid and hands it to you behind your back. You bring the closed box to your forehead, and immediately reveal the color on top of the die. You can repeat this as often as you like.
This miniature colored plastic box is 0.8″ square, with a cube 0.6″ size. Can be examined, and repeated as often as you like.
Also use the miniature die with a paddle move to do a color changing die routine.