Kevin Federline celebrated his 30th birthday this past weekend.  He partied it up at Pure and in Las Vegas.  While he was there he hung out with his ex, Shar Jackson and got a special performance by the Pussycat Dolls.  But, it looks like they partied a little too hard.  Kevin drank one too many Jack Daniels, got on the mike, and started swearing at the crowd.

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

While K-Fed was in Las Vegas Sean Preston and Jayden James were taken care of by their nanny and bodyguards.And in other related news, the Daily Star is reporting that Britney has been hanging out with David Hasselhoff...WHAT?!? First Mel Gibson and now The Hoff???  I'll believe it when I see pictures :)