Forget Madonna going to Pizza Roma - much better news flash ALI G was at Congregation Ramath Orah (Orthodox Columbia U. Shul on 110th and Broadway) for Rosh Hashana Davening 2006! - BUYAKASHA - check it first hand blogged out here  from Da' Minor Fast Day blog - Yes, Mr. Sasha Baron Cohen is a cohen!

From Da Minor Blog:
During Shacharis service at our shul, Ramat Oreh on 110th Street and Broadway, when the Kohanim are called to the Torah, my brother-in-law nudged me and said, "Is that Ali G?" At first he was kidding, but with a closer look it turned out to be Sasha Baron Cohen. Of course, he is a Kohane.

For those not familiar with his Jewish name, you may know him as Ali G or Borat. When he came down from the Bimah, my brother-in-law and I shook his hand and said "Yoshar Koach." Da' Minor blog 

(shkoyach to CJ for the tip)