Michael Kaiser, president of Washington’s Kennedy Center and recently the foremost star of the arts management world, does not surprise easily. But somehow, his friends and supporters managed to pull off a massive surprise party for Kaiser’s 50th birthday this week. “The entertainment was provided by Barbara Cook, Harolyn Blackwell, Patti LuPone and dancers from the Alvin Ailey troupe and American Ballet Theatre. The 136 guests included [Stephen] Sondheim, Supreme Court Justices Sandra Day O’Connor and Ruth Bader Ginsburg, Senate Minority Leader Tom Daschle, World Bank President James Wolfensohn, and lots of other A-list political, business and diplomatic bigwigs.”