Julia Restoin-Roitfeld went as a tamed leopard, Tinsley Mortimer arrived wearing angel wings, and Petra Nemcova donned a Cleopatra wig and eyeliner. But the entrance of the night at Roberto Cavalli's Halloween Ball at Cipriani, which benefited Children in Crisis and the Happy Hearts Fund, belonged to the designer himself. Flanked by six models in feathered headdresses, he arrived on the scene dressed as his famous colleague Karl Lagerfeld. "At the last moment, I thought, 'What am I to do?' " said Cavalli. "I wanted to dress like somebody from my world and my planet. And who is the best? Karl Lagerfeld." When we pointed out that he had some competition in the form of photographer Jeremy Kost, also dressed as the Kaiser, the man of the hour appeared unimpressed. "I have the rings!" he exclaimed. "I have the tie!"

Downtown, meanwhile, the folks behind the Box teamed up with Soho sex shop Kiki de Montparnasse for their Halloween bash. The raunchy Lower East Side cabaret has seen its share of tabloid controversies lately, but the evening was defiantly business as usual. As guests walked into the Kiki boutique, they were greeted by a completely naked woman lying on a table of fresh fruit. Dinner, held in the blackened, candlelit upstairs gallery, was all finger foods prepared by Serena Bass, who took particular pride in the dessert, a strategically sculpted crepe with two ice cream scoops and a strawberry. Afterward, everyone headed over to the Chrystie Street hot spot, where the curtained booths were quickly occupied by Lance Armstrong, Gemma Ward, Mary-Kate Olsen, Josh Hartnett, and—carting around a mold of her head from a recent film— Leelee Sobieski.

— Katie Hintz (Cavalli) and Derek Blasberg (Kiki de Montparnasse)