I was recently directed to the game here, and thought I'd forward it on to you, devoted reader. It's pretty entertaining, and a great way to think about dimensions. If you haven't read Flatland (wiki), you should probably get on that. After that, you can reward yourself by playing the game.
What happens in the game is two dimensional shapes (letters, numbers, etc) get sliced up into horizontal lines, and all you see is a movie of those horizontal lines. It is then your job to figure out what shape the came from. This is very much like the Sphere passing through the plane in Flatland.
Update 9/24: I was just reminded that Google recently did something where you can embed books. Flatland just happens to be one of them:
Hmm, I seem to not have it right. Suggestions anybody?