Supplies: Any pack of crayons
Vincent Vangough was a great artist. He was what people call a "visionary thinker". The truth, Vangough was able to see colors in his mind by feeling them ahead of time. Some people now call this mind reading or ESP (Extra Sensory Perception).
I will demonstrate through this experiment what I mean. "Does anyone have a box of crayons I can borrow?"
By now you have brought your "assistant" on stage. Give them the box of crayons. Turn your back to them and tell them to choose a color, any color, and place it in your hand. You hold the crayon behind your back, then tell them the color they selected.
Secret: While you have the crayon hidden behind your back, make a tiny scrape of the crayon with your thumb nail as you hold your hand to your head.