Caught in the Act!
08/19/2009 AT 06:00 AM EDT
Before coming to Vegas to celebrate with Rumer, Ashton and Demi hung out with close pals Soleil Moon Frye and her hubby Jason Goldberg at a Modart magazine party at L.A.'s Thinkspace Gallery. The happy couple sipped on red wine, browsed the artwork and hung with German street artist Nomad.
In the Big Apple, Rihanna celebrated her assistant's birthday with a bash at Buddakan. The singer and her pals were all decked out in party hats. "She sang 'Happy Birthday' with the whole crew and everything," a source says.
Continuing her baseball-themed road trip, Kate Hudson teamed up with her New York Yankees star beau Alex Rodriguez for dinner at San Francisco's Epic Roasthouse. The two grabbed a back corner table and cozied up over oysters, caviar, filet mignon, a whole fish and some sides.
Michelle Trachtenberg, chatting up revelers at a dinner celebrating the Web site Shopbop.com at New York event space The Smile. "She was super-social," a guest says, adding that the actress talked a lot about fashion. "She was totally the life of the party."
By ALEXIS CHIU, JENNIFER GARCIA, MARK GRAY, LESLEY MESSER and ULRICA WIHLBORG
Tuesday's Caught in the Act >