On his hit HBO television series, "Da Ali G Show," British Jewish comedian Sacha Baron Cohen is after laughs, but in the process he is creating a new form of sociological experiment. Each week, under the guise of three different fictitious personas, Baron Cohen is shown interviewing unsuspecting Americans to elicit outrageous and politically incorrect opinions. His signature character is Ali G, a witless, hip-hopping gangster from the London suburbs; Bruno, a gay Austrian fashion maven, is his most flamboyant character. But it is the genial Kazakhstani television journalist Borat Sagdiyev who has proved to be Baron Cohen's most reliable...