01/19/2010 AT 06:00 AM EST
Golden Globes weekend
got off to a starry start at the Buffalo Club in Santa Monica, Calif., where Creative Artists Agency held a private party on the restaurant's garden patio. Jake Gyllenhaal
chatted up Jennifer Aniston
, and despite his recent breakup, the actor "was in a great mood," a party guest tells us. But the actor spent most of his time talking to his sister Maggie
and Peter Sarsgaard
. Meanwhile, the 200 guests nibbled on hors d'oeuvres like oysters and Ahi tuna carpaccio on the patio, which was decked out with lanterns and candles. "The patio was absolutely packed and the atmosphere was very glamorous and fun," says a source. "Wherever you turned, you would bump into a big movie star."
One such star, Gerard Butler
, was the first big celeb guest to arrive at the CAA party (at 8 p.m.) – and he also was among the last to leave. "Gerard closed the party past 2 a.m.," a source tells us. "He was very nice and thanked the restaurant for a great time." Butler also chatted up his Bounty Hunter
costar Aniston, whom a source describes as a "social butterfly" who mingled with all the guests.
At the InStyle
/Warner Brothers post-Globes bash at the Beverly Hilton, Heidi Klum
enjoyed a sweet end to the evening with hubby Seal
. The two nibbled on Godiva chocolate, with the Project Runway
host grabbing some chocolate macaroons while her husband ate the dark chocolate almond bark. Also having a sweet time at the party: Matt Damon
and wife Luciana
After the Art of Elysium benefit, Gossip Girl
's resident bad boy Ed Westwick
stopped into Teddy's inside the Hollywood Roosevelt Hotel – but he may have been partied out. Westwick, who sported a leather jacket, took a lap around the club and then left after about two minutes. But Lauren Conrad
was enjoying her night out there with beau Kyle Howard
and Lauren "Lo" Bosworth
. The former Hills
star was in the mood to dance – and she got down to classics like Aretha Franklin's "Respect." After an exuberant dance party, the group retreated to a back table where they enjoyed the rest of their night.
Showtime hosted a dinner at Cecconi's Restaurant in L.A., which drew out the stars of their shows, like Edie Falco
), best actress in a comedy series winner Toni Collette
(United States of Tara
) and David Duchovny
). Producers and actors chatted by the bar, sipped champagne and drinks and shared hors d'oeuvres including steak tartare and mini Kobe burgers.
They weren't Golden Globe nominees – but the cast of the Jersey Shore
sure invaded L.A. for the big weekend! Castmates Michael "The Situation" Sorrentino, Nicole "Snooki" Polizzi, Ronnie Ortiz-Magro
and Sammi "Sweetheart" Giancola
were spotted fist-pumping at West Hollywood's nightspot Coco de Ville's Friday night party. Right across the way, James Blunt
hung out with a group of friends, while Jersey Shore
fan Andy Milonakis
took pictures with the cast and posted them on his Twitter, then grabbed the deejay's microphone and started free-styling about his love for the show.
By HOWARD BREUER, DAVID CAPLAN, PERNILLA CEDENHEIM and JENNIFER GARCIAMonday's Couples Watch >