Effect:
You hand a small box of crayons or 3 or 4 different colored crayons to a friend. Tell them you can tell them the color they choose by reading their mind. Have them pick a color and put it in your hands. Without looking at the crayon, you can read their minds, and say exactly what color they’re thinking of!
Secret:
You secretly mark your fingernail with the crayon and sneak a peek at the color.
Performance:
1- Hand the crayons to your friend.
2- Turn around, and put your hands behind your back.
Tell them to pick any color crayon they want, and then put that crayon in your hand (which is behind your back).
3- Once the crayon is in your hand, tell your friend to hide or cover the remaining crayons. When they are hidden turn back around to face your audience, but keep the chosen crayon behind your back.
4- This is where the sneaky part happens! You say to your friend “you could have chosen any color”, or “there’s no way for me to know what color you picked”, while you are talking, you secretly mark your thumbnail with the crayon (in order to get the color you need to scratch it with your fingernail).
5- Have your friend concentrate on the color. Pretend to be reading their minds while bringing your hand (with the crayon mark on the thumbnail) in front of you. It looks like you're trying to read their minds, but you are looking at the color!
6- Once you see what the color is, pretend to concentrate slightly more on reading their minds. NOW, tell them the color crayon they picked.