New Eye Sky
You have a notepad and pencil and you write something down on the pad without the person seeing it. Then, you ask them to think of a three digit number and to say it out loud. And on the notepad is their number!
Before the trick starts, you must have a small pencil stuck to your thumb. When the trick starts, you pretend to write something on the pad but you actually don't. After that, you hand the pencil to the spectator and ask them to think of a 3 digit number and to say it out loud. Then, to buy time to write their number on the notepad, ask them what made them choose that number. Once you have written the number, show them the pad (But not the small pencil!).