Tom Lehrer's last (math) class (2001)

His sudden withdrawal from a successful musical comedy career was a mystery to many.

Well, the official explanation was that Henry Kissinger's winning the Nobel Peace Prize in 1973 made musical comedy obsolete:

  "It was at that moment that satire died," says Lehrer.
  "There was nothing more to say after that."

http://www.bbc.co.uk/bbcfour/documentaries/features/feature_...