sprung up since 2002 offering their own specially-recorded fan-made DVD commentaries. These tracks (usually made available in MP3 format) allow the fans to put forth their own opinions and expertise on a movie or TV series in much the same way as an on-disc commentary. These commentary tracks are played by starting a DVD player with the movie and an MP3 player with the track simultaneously. A substantial community of fan commentators exists, creating many hundreds of downloadable tracks available on the Web. The idea of downloadable commentary tracks has since been co-opted by TV show creators themselves, as creators of TV shows such as the 2004 Battlestar Galactica, Star Trek: Enterprise, and the Doctor Who revival have recorded downloadable commentary tracks meant to be watched along with the episodes as recorded from TV. Mystery Science Theater 3000 head writer and on-screen host Michael J. Nelson has started his own website to sell downloadable commentaries called RiffTrax. He also regularly commentates on the public domain films that colorizing company Legend Films releases on DVD, including Night of the Living Dead and Reefer Madness. Critiques and parodies of the audio commentary The Audio Commentary has been a subject of discussion among filmmakers. Many directors see them as an unnecessary bonus feature, while others record "fake" commentaries, which may contain false information or inside jokes. Other filmmakers have parodied the commentary concept, as the following examples demonstrate. The Coen Brothers movie Blood Simple has a fake commentary written by the Coens and read by an actor posing as a film historian. This "historian", Kenneth Loring, gives information about the production that almost everyone would recognize as being totally ludicrous. He claims, for instance, that one the opening scene was shot upside down with the actors saying their lines backwards and that some roles were reserved for Rosemary Clooney and Gene Kelly. In an episode of The Simpsons ("The Bart Wants What It Wants"), Bart is watching an Itchy & Scratchy DVD and decides to turn the commentary on. A small box appears at the corner of the screen, showing Scratchy ("We shot this at four in the morning, and the crew was getting a little cranky") and Itchy ("You can never get enough takes for Steven Soderbergh"); midway through Scratchy's next sentence, Itchy cuts off his head. Welsh comedian Rob Brydon starred in the ITV comedy show Director's Commentary (2004) in which