Blake Lively made her debut on The Late Show with David Letterman last night.  The Gossip Girl first greeted fans in what  appeared to be nothing more than a man's dress shirt; um, did you run out of the house, Blake?  The second dress was indeed an actual dress, a blue chiffon number with a black slash.  But still, what the hell was that shirt she was wearing before? Anyone know what was up with that?