I remember the Johnny Carson show with Jerry Lucas who had memorized portions of the Manhattan phone directory. I don't know how big the "portions" were. I don't believe it was staged, I truly think he actually did it. Johnny picked several names at random and the guy gave the correct number and the names and numbers directly above and below. I don't think Carson would have risked doing a staged appearance. It would have destroyed his career had it been disclosed. I also can't fathom how one could cheat. Maybe an earphone or Morse Code stimulator strapped to his thigh. Possible but unlikely. The foil would have to have been in the audience with a phone book and a telegraph key. It was not live but taped at 6PM Pacific.
PS - I memorized Pi as 3.1415 9265 3589 as a teenager.