For 11 years, from its beginnings as a local public-access cable TV show to national exposure on Comedy Central and the Sci-Fi Network, “Mystery Science Theatre 3000” was an oasis.

There, thanks to a misplaced janitor on a spaceship and two robots he built from crude parts, bad — really bad — movies were heckled throughout each episode of the series.

“MST3K” left cable TV in 1999, but its spirit lives on in Rifftrax, where show writers Bill Corbett, Kevin Murphy and Michael J. Nelson (the latter of whom became the TV series host in 1993 through its 1999 conclusion) do the heckling.

“The main difference is that we don’t have a fictional framework around it anymore with the spaceship and the puppets,” Corbett said in a telephone interview from Minneapolis. “The only characters we play are ourselves.”

Rifftrax got its start 6 1/2 years ago and broadened its range from bad sci-fi and other movies to more “big Hollywood stuff,” Corbett said. Its first endeavor was selling MP3 tracks since they didn’t have the rights to package and sell the movies themselves.

“People can buy that and roll it with their ‘Star Wars,’ ‘Avengers,’ whatever,” Corbett said.

It also turned into a public presentation and was beamed into movie theaters nationwide, including Rave Cinemas in Davenport, for the live experience.

During the next two Thursdays, some of Rifftrax’s “greatest hits” will be repeated: “Manos: Hands of Fate” on Jan. 24 and “Plan 9 From Outer Space” on Jan. 31.

“Manos,” Corbett said, is one of the few exceptions to a Rifftrax rule that they couldn’t do a movie that’d been done on “MST3K.”

“We mostly avoided the old stuff, mostly because it’d been done,” he said. “Manos” is “right up there in the top five movies that people associate with the worst movie of all time.”

The live-to-theaters shows have been produced in and around Nashville, where the trio was working with a country music producer who’d had success with the format.

With two new, younger writers, the scripts are composed after several viewings of a given film. Although the onstage responses seem spontaneous, nearly everything is scripted.

“We, and I don’t think anybody in the world is so brilliant that they can come up with the jokes that we do (on the spot),” Corbett said. “It would be a bunch of guys fumbling around and occasionally getting in a good line.

“We’ve developed an ability to make it seem otherwise in our performances. But we’re not hiding it from anybody since we’re onstage reading the script,” he added.

Besides the “greatest hits” of repeats this month, Rifftrax does the theater screenings twice a year.

“That might increase, but our feeling now is that they’re special events,” Corbett said. “If we populated the air with too many of them, they wouldn’t be so special anymore.”