Jon Gosselin Is A Vegas Party Boy

Jon Gosselin hosted a pool party Saturday night at Wet Republic at the MGM Grand Hotel & Casino, and the lady he brought along wasn't Kate, Kate  2.0 or even Hailey but his mom Pamela!

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Jon joins an illustrious list of ex (or soon-to-be) husbands - think Kevin Federline - who have pulled in a few extra bucks by hosting Vegas events.  But he did draw a crowd, and signed hundreds of autographs in the process.

Estranged wife Kate Gosselin is on kid duty at home in Wernersville, PA.

A new episode of Jon & Kate Plus 8 airs Monday night on TLC.