The Vienna Life Ball isn't one of those fancy dress parties with a few C-list socialites in borrowed gowns. With 2.5 million liters of water trucked in to surround the town hall, in keeping with this year's aquatic theme, and 40,000-plus guests, Saturday night's 17th annual installment of the HIV/AIDS fundraiser could only be described as, well, splashy. Katy Perry and Róisín Murphy performed and Pamela Anderson, Eva Longoria Parker, and Bill Clinton, whose foundation was one of the event's beneficiaries, made cameos. "Many of you know me as the Nanny," said Fran Drescher, introducing Clinton. "But I'm also the public diplomacy envoy for women's health issues, which means I answer to Hillary Clinton. Do you think you can put in a good word for me, Bill?" The former POTUS laughed. "She's a tough boss," he said.

Clinton had plenty of fans, but the evening's star attractions were the costumes people put together. There were sexy pirates, mermaids and mermen, kinky sailors with anchor-shaped nipple clamps, starfish, gallons of body paint, and more underwear-as-outerwear than a Victoria's Secret catalog. "My only complaint is that every time someone asks for a picture with me I walk away covered in body glitter," Perry joked after her performance, which had her climbing out of a giant shell à la Venus. "But I've been covered in worse."

— Derek Blasberg