More magic toys at GDC that I would cheerfully have sold my best friend to posses when I was a child if I had had a best friend. Who knew that the future held these things? First, there's Crayon Physics Deluxe which is literally a MAGIC BOOK - I have no other way to say this. You draw on a page, and your objects take on weight and crayon-y substance (see picture) - you're literally drawing into a little 2D crayon world. It's a puzzle game, too, but I find it hard to care next to the bowel-loosening thrill of seeing objects, fresh from the artist's hand, fall or roll away.
The Playstation Eye Tank War Demo seems to spring from the same purple crayon - you draw something, freehand, and drop it into a video game where it rolls around shooting at other things. If you claim that you did not draw things shooting at other things in the margins of your school notebooks, then you, sir, are a liar.