David Pogue has written an interesting article in the New York Times about iForce, and how magicians love it but also hate it. Why? They love it because it's such a powerful trick. They hate it because, at $2.99, it makes the barrier for entry so low. Anyone can be a magician. And this app blows people away. You write down a prediction on your iPhone, then put it face down on the table. Then, for example, you ask the person to give a number between 1 and 8. Then you turn over the phone and they see that that's the number you'd written down. The video shows how impressive it is.