I've been looking all over for this I saw several days ago. Finally thought to do a search thru Ixquick and voila:

If this is real and not a "plant" to make the Prez look bad, then this takes the cake.

Here's a site that carried the story with some extra tid bits on a Philly speech book- throwing and a streaker too: (Does the streaker win the million dollars?)

http://americangrandjury.org/casting-for-barack-obama-townhall-meeting