WHEN “Mystery Science Theater 3000” was canceled after 11 seasons in 1999, 146 distraught fans bought a full-page advertisement in Daily Variety urging another network to continue the show. But the series was not revived, and today devotees cannot even tune in to reruns because its premise — a host and his two robot pals mock B movies — required securing those movies’ broadcast rights, which expired after the show’s demise.

But those self-described “Misties” are welcoming a resurrection of sorts. Mike Nelson, the show’s longtime host and head writer, has begun a new venture called RiffTrax, and he can now skewer virtually any movie without infringing on copyrights. Recordings of him talking back at movies can be downloaded (for fees ranging from 99 cents to $3.99) from rifftrax.com. Start playing the DVD or VHS version of the movie and Mr. Nelson’s commentary simultaneously, and the effect is that of a director commenting on a DVD — except that Mr. Nelson is inclined to say, as he does during a scene in “Star Trek V: The Final Frontier” in which William Shatner climbs a mountain, “He’s actually trying to scale his own ego.”

So far there are more than 30 RiffTrax episodes, including “The Matrix” and “The Lord of the Rings: The Fellowship of the Ring,” with Mr. Nelson adding three or four more titles every month. He said in a phone interview from San Diego, where he lives, that “hundreds of thousands” of the files have been purchased for download so far. (A spokesman for Legend Films, which produces RiffTrax, declined to clarify or confirm Mr. Nelson’s claim, saying the company considers sales figures proprietary.)