Simpson Sisters Party at the Palms

Jessica parties with her sister, Sarah Larson shows solo, and Lauren Conrad cozies up to Stephen Colletti

It was a tale of two Simpsons at the Palms Place grand opening in Las Vegas this weekend.

Jessica and Ashlee Simpson-Wentz both came for the party, where Ash's hubby, Pete Wentz, was deejaying.

Ash was "glowing" as she sipped on water, says an eyewitness. Proud papa-to-be Pete even dedicated a song to "his baby mama" after his set, and the newlyweds looked lovey-dovey throughout the night.

Jess, however, looked less-than-thrilled to be there. "She didn't smile at all," says our source. Missing Tony Romo, maybe?

Looking happier was Sarah Larson, who was out for the first time since her reported split from George Clooney. She shared a cabana with an ex-boyfriend and was drinking and dancing. According to a friend, she's trying to put on a brave face despite the breakup.

Linda Hogan appeared to be doing just fine, as she channeled her inner cougar. Hulk's ex-wife made out with her 19-year-old date.

Lauren Conrad also was on hand for the bash—and hanging with Stephen Colletti. The two exes are rumored to be back on, yet again.

Do we even care anymore?

—Additional reporting by Claudia Rosenbaum