US Penny, Canadian Penny
A penny is shown to the spectator and rubbed with the thumb to apparently generate heat on the coin. The hand then squeezes the Penny to slightly bend it. Once again, the Penny is rubbed to generate more heat to the coin. The Penny is squeezed yet again and shown to be extremely bent. The Magician then uses the other open hand to rub & press the Penny flat in to its original shape.