penn & teller do not seem to like mentalists, they seem to be get annoyed with them.
i'm pretty sure as you guys mentioned, something with the brick/house trick was actually written or drawn in/on his hand. you can actually see it here:
i also thought the end p&t pretty much gave it away with the way they were mocking his "pantamime" of the book, and the guy in the audience even said yes that pantamime sure helped him "imagine" the word he said!
i thought the guy w/ the cup & balls was pretty awesome.