The PYTs from Gossip Girl are really taking advantage of their newfound fame and open invitation to fancy parties. Blake and Leighton (S and B, respectively) were at Saturday night's launch of Tiffany's 2008 Blue Book Collection at the Museum of Natural History in NYC. Something about Leighton looks different (older), but obviously these girls look adorable in any dress and especially great up against that Tiffany blue.