Filk

A filk is a song, usually a traditional or well-known one, for which the words have been re-written by fans for a specific fandom.

The origins of the word aren't known for sure, but it is suspected that it's a typo of "folk." This interpretation makes sense in context with the probable origins of filking, which seem (like so many fandom-related things) to be sci-fi conventions: the con-goers who wrote the filks would set them to traditional folk tunes to ensure that lots of people would be able to sing along with the new lyrics.

Filks and filking should not be confused with songfic, which is an entirely different critter.

PPCers are responsible for a fair bit of filking. For example, see the PPC Holiday Songbook.