Well-heeled guests put on their fashionable best to attend events around NYC last night. The week's festivities kicked off with some dramatic ball gowns, including Chanel Iman's hot pink number, at the American Ballet Theatre's Opening Night Spring Gala. At a slightly more casual gathering, Julia Restoin-Roitfeld went for all white to celebrate the launch of her new site, RomyAndTheBunnies.com. Click through to see who else made our best dressed guests from Monday night.