Italian Prime Minister Silvio Berlusconi’s biggest critic these days comes from the stage, where Dario Fo unleashes his criticisms. “For all its grave accusations, “The Two-Headed Anomaly” is an almost vaudevillian romp. The show consists largely of short, fat and bald jokes about the prime minister and his councilors. It stages bawdy attacks not only on Mr. Berlusconi’s politics but also on his personal life and his ethics. But that is exactly what Mr. Fo’s fans expect and want.”