Mariah Carey and Nick Cannon
After performing at Atlantic City's Borgata Hotel Casino & Spa on Saturday night, Mariah Carey
kept the party going until the wee hours, joining husband Nick Cannon
as he deejayed in club mur.mur. "Security literally cleared a path for her to walk through," says a witness. "She was surrounded by handlers." Carey spent her night singing along "to just about every song" – including her own, "Emotions" – and happily posed and waved for fans while giggling with her dancers. When Cannon's set wrapped around 2 a.m., Carey joined him in the deejay booth to close out the evening.
enjoyed her first-ever visit to Chicago on Saturday, joining her band for dinner at Asian eatery Sunda, where a source says she "was laughing and looked like she was having a lot of fun." Later the group made their way to club Underground, where they hung out backstage, imbibing in Grey Goose and champagne. Meester then hit the stage for a "very un-Blair-Waldorf-like" performance, complete with head banging. She "sounded great," adds the source.
hunk Adrian Grenier
got cozy with a mystery blonde while welcoming 2010 with his band, the Honey Brothers. The guys led the countdown to midnight at a Maestro Dobel Tequila event at Boston's Roxy nightclub before toasting with tequila – and jamming all night long. According to a partygoer, fans "lined the dance floor" as Grenier got down on drums and guitar.
Diners at Steak 954 in the W Fort Lauderdale had a brush with fame on Friday as Jamie Foxx
stopped in to celebrate a friend's birthday. The actor serenaded his female pal with a rousing rendition of "Happy Birthday" – thanks to a little help from other restaurant patrons. When it came time to order, Foxx skipped the menu, instead asking the waitress to make some savory selections for him.
Also celebrating a birthday this weekend was Dancing with the Stars
pro Karina Smirnoff
, who spent an evening surrounded by friends including Lance Bass
at PURE nightclub in Las Vegas. Donning a sleek white dress and matching Christian Louboutin heels, Smirnoff commemorated the occasion with some vodka cocktails, and was elated when the Las Vegas Pussycat Dolls presented her with a cake in front of clubgoers.
By JENNIFER GARCIA, MARK GRAY, JESSICA HERNDON, LIZ MCNEIL and AINKA SHACKLEFORDMonday's Couples Watch >