8. Mickey Rooney
Episode: 'Radioactive Man', Series 7 (1995-'96)
Rooney is desperately funny and self-effacing as a parody of his fallen child-star self (the cartoon image of him squeezed into Milhouse’s spandex Fallout Boy outfit is equally disturbing and priceless).
He was a joy to work with, too. Nancy 'Bart' Cartwright remembers him being happy to do all his voice work alongside the other actors (unusual, apparently) and being “full of pep”.
7. Mel Gibson
Episode: 'Beyond Blunderdome', Season 11 (1999-2000)
Another ace self-effacing appearance from a Hollywood high-flyer, this time with Mel Gibson taking notes on his latest blockbuster from a jealous, idiot-brained Homer.
The result: a remake of Mr Smith Goes To Washington in which every member of Congress is graphically slaughtered, with enough Tinseltown in-jokes to kill a small horse (“I second that motion… with a vengeance”).
6. Adam West
Episode: 'Mr. Plow', Season 4 (1992-'93)
Episode writer Jon Vitti weaved West into the story just so he could finally meet the camp Batman legend.
West sends himself up brilliantly (“I didn't need a moulded plastic suit to improve my physique – pure West”). Matt Groening has since said that the TV star was one of the most popular guest performers among The Simpsons’ crew.