But arguably, everyone was a winner tonight! Models, socialites and actresses including Jennifer Connolly, Kate Bosworth, Liv Tyler and the Olsen twins power-shopped in (and for) ball gowns before a seated dinner with a medieval theme. Among the bargains: Christian Louboutin espadrilles for $108; a sparkly, fur-trimmed Proenza Schouler flapper dress for a measly $2,048.

Designer Marc Jacobs arrived hand-in-hand with boyfriend Jason Preston, a self-described “personal assistant”; super-mannequins Naomi Campbell and Kate Moss laughed with photographer Mario Testino; bridal empress Vera Wang brought first lady fave Arnold Scaasi as her date.

Design scion Margherita Missoni, in gray Missoni gown, slipped on a pair of J Brand jeans ($53) under her dress, as flashbulbs popped. “I just bought a watch for my mother,” Ms. Missoni said. “She’s in bed in Italy.” For herself, she had bought “a lot of Ralph Lauren sweaters.”

Ralph Lauren himself was in attendance, along with wife Ricky; also their elder son David and his girlfriend, Lauren Bush. The latter two stole a private moment in housewares as dinner was beginning. Lauren fils, wearing a puffy ski vest, was weighing two modest purchases. “Either a book or chocolate,” he said. C’mon, live a little!

A selection of expensive framed photographs near the bar was mostly marked with “sold” signs. “I love this one. It would look great in my dressing room,” said another Lauren, socialite-Vogue contributor Davis, dragging a friend over to an $18,000 Testino print of model Stella Tennant.

Meanwhile, actress Mary-Louise Parker, wearing a short black bejeweled Marc Jacobs dress, wandered around with her sister, Sage. “I’m here for the cause, but now that I’m here …” Ms. Parker said. Suddenly, she caught sight of the children’s section. “Little people’s clothes! I didn’t know they had little people’s clothes!”