Madonna was riding high in 1985. Her second album, Like A Virgin, had produced a string of hits; she starred in the movie Desperately Seeking Susan; the song Crazy for You from the movie Vision Quest became her second #1 hit; TIME Magazine had her on its cover in May; and in August (on her 27th birthday) she married actor Sean Penn. And a scandal only added to her "buzz" when Playboy published nude photos of her (from her past) in its September issue.
With all that was going on in her fledgling career it was a no-brainer for Saturday Night Live to have her host the first show of the 1985 season on Nov. 9. Surprisingly, she wasn't called upon to sing - that honor went to the group Simple Minds (she'd get the chance in January 1993). One of the skits had her portraying Princess Diana visiting the Reagans with Prince Charles (played by Jon Lovitz).
Although this would be her only time hosting, Madonna made a number of memorable cameo appearances over the years. For instance she appeared on "Coffee Talk" (to the surprise of everyone Barbra Streisand showed up at the end of the segment) and in 2009 she and Lady Gagy had a catfight - but my favorite cameo by far was her May 1991 appearance in a "Wayne's World" skit. (It aired the same weekend as her Truth or Dare documentary opened.)