The Costume Institute at the Metropolitan Museum of Art held its annual gala last night, celebrating the Institute's new exhibit, "Poiret: King of Fashion." The theme for the night? Freedom, as Paul Poiret famously released women from the confines of corsets. And perhaps in his honor, or at least continuing in his tradition, Jessica Simpson nearly busted out of her Roberto Cavalli dress, while the usually well-dressed Julianne Moore was thisclose to having a nip slip in her white tuxedo blazer. Kate Moss, America Ferrera, and Cameron Diaz, however, all looked stunning. But the big winner was Sandra Bullock — yep, Sandra Bullock! — who looked drop-dead gorgeous. There are pics of all of them, plus many, many more, in our Costume Institute slideshow.