After more than a year of reworking his image into that of a latter-day Ward Cleaver (only with saggy manpris instead of a cardigan), Kevin Federline tossed a monkey wrench into his well-oiled PR machine while celebrating his 30th birthday in Sin City Friday night.

The former dependent spouse of Britney Spears was booed and given the hook after an extended, expletive-packed turn at the microphone during his bash at hot spot Pure.

"The DJ tried to take the microphone back after about three minutes, but he just kept going," an eyewitness tells Us. "It didn't make any sense what he was saying. He was just blabbing on."

At one point, the natty gray suit-sporting Federline shouted to the crowd (via TMZ.com), "I lost my voice at the craps tables. I lost all my money."

One of his pals eventually did him -- and everyone else -- a favor by pulling him off the mike.

No word on whether the cash the Jack Daniels-quaffing, couch-dancing (per People) K-Fed supposedly gambled away was the fee he received to ring in his milestone at the nightclub.

According to the New York Daily News, Federline may have pocketed between $100,000 and $300,000 to bid goodbye publicly to his 20s, a momentous decade that saw him father four children, unleash the aural horror that was "PopoZão" and build up his nest egg courtesy of his deep-pocketed ex-wife.

On hand to help Federline mark the auspicious occasion was the mother of two of those kids, Shar Jackson, whose coziness with her onetime squeeze raised some eyebrows.

"They looked like a couple again," a spy tells the paper.

But an insider pooh-poohs to FoxNews.com, "Shar and Kevin are very supportive of each other -- they have children together so of course they have a special bond. But Shar being there meant nothing romantically -- they are just friends."

Also taking part in the festivities: Kevin's cucumber-cool, payment-collecting lawyer, Mark Vincent Kaplan, and the Pussycat Dolls, who serenaded him with "Happy Birthday" before smearing cake all over his face, a frosting blitz that reportedly set off an "Animal House"-like food fight.

Sean and Jayden spend Easter at home in Tarzana, Calif., with nanny and bodyguard on March 22.

So, where were sons Sean Preston, 2, and Jayden, 1, while their dad cut loose and wasted perfectly scrumptious birthday cake?

Paparazzi caught the tots in the care of their nanny and bodyguard, who treated them to a trip to a kiddie play group.

As for Britney, OK! reports she spent Easter in Malibu, Calif., with parents Lynne and Jamie, with the three spotted taking a walk along the beach.

Next: Romance Report: Kate & Owen, Posh & Becks