I'll pass on Borat too, but is Ben Stein mistaking Borat's over the top anti-Jew rantings for some po-mo attempt at skewering the very anti-Semitism he seems to perpetuate? Or am I giving Borat way too much credit?
Yes, Sacha Baron Cohen is playing a character that is a sort of backward guy from Eastern Europe who uses over-the-top stereotypes as a way to get reactions from real people. He then films those real people and the results could not have been scripted better.
He does the same thing with Ali G, his white British "ghetto" character who spouts Jamaican and rap-based jive, and Bruno, a gay Austrian fashion reporter.
It is actually very inventive and funny, and his character comedy is flawless.
I really like Ben Stein, but he really didn't get the style of comedy, or the point.