For anyone who's ever wondered if, say, Lisa Kudrow is jewish (she is) - there's Jew or Not Jew a site dedicated to debating, identifying and rating the jewish-ness of famous people - real (Jason Schwartzman) or imagined (Max Fischer - Schwartzman's role in Rushmore).
Of particular interest is the debatable jewish-ness of Simpsons newscaster Kent Brockman. One episode reveals Brockman's on-air name was "Kenny Brocklestein" in the late '60s, but there are others showing Brockman attending church on Sunday. Go figure.