Jon Hamm Hangs With Sean Penn ... Until 2:30am!

Now we know where the real party is at on Wednesday nights!

Sean Penn and Jon Hamm had dinner at Dan Tana's yesterday evening, and the hunks didn't leave until 2:30am! Sean quickly jumped into his waiting car, and Jon, who looked more like his Mad Men character Don Draper, seemed a bit surprised by all the attention from photographers. However, he was kind enough to sign a handful of autographs for fans...