Keith Barry describes himself as a mentalist. He steps onto the TED stage to perform some brain magic in one of my favorite videos of all time. Magic is mastery of the human brain, and Keith Barry is a grand master. I showed this one to every class, mostly to get them interested in TED.
After showing this in class, I learned some of the techniques. I tried teaching this kids how to read someone's mind and here is one to try. Have a partner pick a number 1 to 20. Start counting from one and carefully watch their pupils. While there face may not react when you get to the number, their pupils will never lie. When you see them change, that should be the number. The change is subtle and it clearly takes years of practice to master. Notice that Keith performs the feat with letters to determine the ex-boyfriend's name. Small reactions and experienced guessing gets him to the right answer.
Enjoy and see if you can figure out the Coke bottle trick!