In the club: Simpson celebrates the milestone in Las Vegas. Plus: Ben & Jen and more

FASHION ROCKS

Mischa Barton gives a sweet smile as she leaves West Hollywood nightclub the Viper Room early Friday morning. The actress had gone to see Whitestarr, the band fronted by Kimberly Stewart's ex-fiancé (and, reportedly, Barton's new beau), Cisco Adler.