Ashlee Simpson, Pete Wentz and son Bronx, on March 31
05/30/2011 at 03:00 PM EDT
and Ashlee Simpson
shared a casual lunch at Carney's in Studio City, Calif., with their son, Bronx. The estranged couple, who have kept things "amicable,"
were "smiling and having a sweet time with their son," an observer says. "They definitely looked like a happy family – very chatty and smiling a lot. [They were] very attentive to their son."
and beau Olivier Martinez
cuddled up at the grand opening of Las Vegas's Nikki Beach inside the Tropicana. Though the theme of the party was white, Berry wore a brown dress. (Martinez's white button-up shirt fit the theme, though!) The duo sipped champagne in a VIP area of the club as they watched fireworks and live music performances in the new venue.
celebrated his 28th birthday at Gallery Nightclub inside Planet Hollywood Resort & Casino – and he enjoyed champagne with longtime girlfriend Kourtney Kardashian
and some close friends. The couple looked excited and laughed when Disick's birthday cake presentation began. (A troupe of feather-waving dancers brought up a lavish cake from Sugar Factory.) After dessert, the two wasted no time dancing and enjoying their evening with friends.
and boyfriend Matt Rutler
grabbed a table near the deejay booth at new L.A. nightspot The Beverly. The singer had two bodyguards in tow, as well, and was in an upbeat mood, giggling and dancing in her seat to the tunes before getting up to dance more. Aguilera also made time to snuggle with Rutler for a bit before heading out just 15 or 20 minutes after arriving at the club.
and his pregnant wife Naomi
checked out the VIP preview night of Tim Burton's exhibit at the Los Angeles County Museum of Art. Knoxville kept his arm around his wife as he guided her through the museum. The Jackass
star mingled with fellow museum patrons, including one man with a baby, and also paused to snap pictures on his phone of some of Burton's sculptures. The couple also stuck around to catch a surprise performance by Jane's Addiction.
By JENNIFER GARCIA, MARK GRAY, MONICA RIZZO & JESSICA WEDEMEYER