Caught in the Act!

• Jennifer Aniston, having a girls' night at famed Beverly Hills eatery Spago, where her group shared several of chef Wolfgang Puck’s signature dishes. "They were having a marvelous time," says a source. "Jennifer was laughing all night."

• Jessica Simpson, chilling out at a corner table with friends – and soon joined by sister Ashlee – at the Tropicana Bar at the Hollywood Roosevelt Hotel. On another night, Kate Hudson and Owen Wilson held court at the hot spot with a bunch of pals while Leonardo DiCaprio partied with Kevin Connelly and Nicky Hilton.

• Madonna and husband Guy Ritchie, dining at the five-star restaurant at Rome's Hotel de Russie while a wedding party had their reception nearby. "When they walked in, everyone went quiet for a few seconds," a source tells us. After the celeb duo finished their meal, “the groom asked them if they would toast with them. They got up and went over to the newlyweds' table and toasted to the bride and groom."

• Tara Reid, hitting the party circuit over several days in Miami. First She hung out at an afterparty at club Mansion for swimwear designer Rosa Chá's new line. Two days later she went to Snatch and spent the wee hours at BED. The following night, it was off to a bash for designer Shay Todd and then a soiree at Rok Bar. Then the next evening she hung out with Russell Simmons at The Forge restaurant. On her final night in town, she swigged Cristal with friends at the Skybar.

• Will Ferrell, making his grand entrance in a racecar at the Hollywood premiere of Talladega Nights: The Legend of Ricky Bobby. Does the funnyman feel the need for speed in real life? "It depends. Freeway driving, I like to go 120 mph. City driving, not much slower – about 116 mph," he joked to us. "I got my license taken away about four times – that's okay."

• Lauryn Hill, giving a surprise performance at the fourth annual Rock the Bells Hip-Hop Festival in San Bernardino, Calif. She sang hit songs including "That Thing" and "Fugee-La." Meanwhile, the Black-Eyed Peas' Will.i.am watched pals Mos Def and Talib Kweli's sets from backstage.

• Rachel Bilson and Zach Braff making the scene at a listening party for the upcoming soundtrack to their film The Last Kiss at West Hollywood club Privilege. Braff, who is rumored to have split with girlfriend Mandy Moore, attended solo. But Bilson was there with boyfriend Adam Brody, who told us that the actress is "super-excited" about starring in her first movie.

• VANESSA DIAZ, KIMBERLY LANSING, JENNY SUNDEL, PRAXILLA TRABBATONI, JON WARECH and NICHOLAS WHITE (People.com) Click in above... or visit our home-page for more celebrity gossip