Mayor Bloomberg, in his ripped jeans, shades, and a hideous flower-print shirt, joined the cast of Hair onstage at last night’s Inner Circle dinner and did what mayors always do at these things: made a fool of himself. After riding on to the stage in a van filled with pot smoke (we’re not sure if this violated the smoking ban), Bloomberg halfheartedly sang along to “Age of Aquarius” before his friends Howard Wolfson, the Situation, and Snooki emerged from behind the curtains. Fortunately, they all kept their clothes on and none of them dressed in drag, which means Bloomberg still hasn’t matched Rudy Giuliani’s performance from 2000. But Bloomberg still has time to make that happen. He just needs to find a dress that fits.