"Mork Goes Erk" is the seventeenth episode of the first season of Mork & Mindy. The episode first premiered on ABC on February 8, 1979. "Mork Goes Erk" was later released on VHS on January 1, 1998 as part of a two-episode special which also included "Mork's First Christmas," and on DVD on September 7, 2004 as part of the "Mork & Mindy - The Complete First Season" DVD boxed set. In the episode, David Letterman portrayed a Werner Erhard-like character by the name of "Ellsworth" offering ERC or Ellsworth Revitalization Conditioning. Mork and Mindy attend one of Ellsworth's trainings at the suggestion of their friend Susan, where they endure Ellsworth's authoritarian brand of group therapy. Mork points out hypocrisy in Ellsworth's teachings, and exposes him as a fraud. The episode has been placed in a sociological context, and compared to the Erhard Seminars Training or "est" course.