RiffTrax is an American company that produces scripted humorous commentary tracks which are synced to feature films, education shorts (mostly public domain), and television episodes.

[1] The first releases originally featured Michael J. Nelson, Kevin Murphy, and Bill Corbett, through audio-only tracks intended to be played in unison with unaltered VHS and DVD copies of these programs.

After the introduction of already-synced VHS and DVD material, added to the riffers were Mary Jo Pehl and Bridget Jones Nelson, who also wrote and performed for the MST3K series.

Guest riffers have also added commentaries, including parodist "Weird Al" Yankovic, comedians Paul F. Tompkins, Cole Stratton and Janet Varney, and actors Joel McHale, Fred Willard, and Neil Patrick Harris, among others.

During this time, Rhino Entertainment collaborated to produce four riffed films on DVD: Hollywood After Dark, Killers from Space, The Wild Women of Wongo, and The Giant of Marathon.

[2] The movies chosen for Mystery Science Theater 3000 were predominantly low-budget B-movies because the show itself was low budget and producers could only afford films in the public domain or otherwise cheap licenses.

[3] Nelson had researched bringing about directly releasing DVDs of films with the commentaries included, then realized this initial idea was not feasible since he would be "sued out of existence.

[5] There would be no legal or monetary restrictions to prevent RiffTrax from producing them,[6] though viewers would have to play their own physical copies of the films at the same time.

The company originally produced audio-only tracks which were intended to be played in unison with unaltered VHS and DVD copies of these programs.

Guest riffers vary often; other MST3K alumni have been featured, such as Pehl and Jones Nelson, in addition to Internet personalities Richard Kyanka (of Something Awful fame), Josh Fruhlinger (writer of The Comics Curmudgeon) and Chad Vader, as well as actors Harris, Willard, and McHale, and parodist Yankovic.

[8] The success of the guest format is such that "Three Riffer Editions" of some films previously solo riffed by Nelson have been re-produced for VOD services.

They have also since expanded to produce full-length video-on-demand riffs for films that have entered the public domain or otherwise have been licensed cheaply, such as Night of the Living Dead and Santa Claus Conquers the Martians.

[15] As part of SF Sketchfest in San Francisco, California, Nelson, Murphy, and Corbett have appeared several times performing live riffs alongside a screening of a film.

[16][17] The RiffTrax crew have done live internet broadcasts on Ustream.tv, riffing public domain films and taking viewer questions.

The first show was performed live at the Belcourt Theatre in Nashville, Tennessee on August 20, 2009, where Mike, Kevin, and Bill riffed Plan 9 from Outer Space, along with the short film Flying Stewardess and guest appearances by Veronica Belmont, Jonathan Coulton, and Rich Kyanka of Something Awful.

show in theaters took place on December 16, 2009, where they riffed several Christmas short films, one featuring special guest Weird Al Yankovic.

[19] A fourth live show riffing House on Haunted Hill, also filmed at the Belcourt,[20] occurred on October 28, 2010, with special guest Paul F. Tompkins.

The successful Kickstarter allowed them to riff on The Room, Sharknado 2: The Second One, Miami Connection, and Santa and the Ice Cream Bunny at different live events throughout the year.

In August 2008, Nelson, Corbett and Murphy formed a musical trio named The Rifftones, initially to compete in Quick Stop Entertainment's second Masters of Song Fu competition.

They won the competition, beating fellow musicians Jonathan Coulton, Paul and Storm and, in the final round, Jason Morris.

[48] Though RiffTrax are suggested to be played on an MP3 player or with computer software, they are sold as unrestricted MP3s, allowing users to choose the viewing method that suits them the best.

RiffTrax On Demand has released many short, public domain, and educational films similar to the ones that MST3K would sometimes mock before a full-length movie began.