Source : Free On-Line Dictionary of Computing

filk
     
        /filk/ [SF fandom, where a typo for "folk" was adopted as a
        new word] A popular or folk song with lyrics revised or
        completely new lyrics, intended for humorous effect when
        read, and/or to be sung late at night at SF conventions.
        There is a flourishing subgenre of these called "computer
        filks", written by hackers and often containing rather
        sophisticated technical humour.  See {double bucky} for an
        example.  Compare {grilf}, {hing} and {newsfroup}.
     
        [{Jargon File}]