An interesting side note on Homer J. Simpson's beverage of choice is that there really IS a Duff Beer. It was brewed and distributed in New South Wales, Australia. They were sued by the producers of the Simpson's because of the use of Duff on their cans in such a manner that was very similar to the Simpson's. The exact order was (according to law.harvard.edu) to restrain the South Austrailian Brewing Company from "promoting or dealing with any product in the form of a can" ... "with the wording, get-up and name".

Duff Beer (along with many other references to the cartoon) are all under trademark, and are thus protected internationally. Groening and friends prevailed, forcing Duff Beer to be a rarity and thus quite a collectors' item.