Since events hatched by the Dazed & Confused magazine crew tend to produce cheek-to-stiletto crowds, the invitation for Thursday night's Mini Cooper rooftop fête begged recipients not to forward or even pre-blog about the party. "I think that was a smart idea. I wish all parties were like this," said Mary-Kate Olsen as she settled onto a populated but not too populated grassy knoll opposite the DJ booth where her rumored paramour, Nate Lowman, was spinning. Elsewhere on the mini mountain, Julia Restoin-Roitfeld lounged with pals while Jessica Stam found herself trying to sit like a lady in a short dress. "Trying and failing," she said. Unwanted party crashers weren't the only ones who missed out on the shindig. Dazed publisher Jefferson Hack had opted to stay in London; Mark Ronson's birthday in the English countryside apparently took precedence. What's more, the evening's entertainment—indie rock It band MGMT—almost didn't get to perform its addictive-as-crack anthem "Time to Pretend." In a misguided effort to maintain the party's aforementioned guest-to-space ratio, an overzealous security guard tried to keep the band from taking the stage and nearly incited a riot in the process. Monet Mazur happened to be nearby and witnessed the scuffle. "That could have gotten really bad," she said after dodging a shower of airborne water bottles. Happily for her, she came away unbruised, and the band played on.

— Derek Blasberg