Stars like Will Ferrell, Matt Damon, Oprah Winfrey and Kermit the Frog all stopped by
Played: Prince Gerhardt Hapsburg in season 1's "Black Tie"
Even on a show that included Paul L'Astname, Dr. Spaceman and Jon Hamm in blackface, no guest character may have been stranger — nor guest performance more committed — than Reubens as the European royal whose body is a horror show thanks to "centuries of inbreeding." He can't wink properly, speaks at randomly-shifting volumes, has a doll's hand where a real one should be, can't dance due to having no fluid in his joints, and is unable to process grapes. It's that last fact that becomes the most crucial one, when he intentionally drinks a fatal glass of wine after coming to believe that Jenna has fallen in love with him. I can think of a handful of actors who could have gone to such a deranged place as the sometime-Pee wee Herman, but none who could have played the part better.
- Alan Sepinwall