Stage productions based on movies may be theatre du jour on Broadway, but the Scottsdale Desert Stages Theatre is experimenting with the slowly growing idea of converting beloved television sitcoms into musicals and plays.

In the spotlight: “Gilligan’s Island: The Musical.”

Written by Sherwood Schwartz, creator of the original 1964 TV sitcom, and son Lloyd Schwartz, the musical follows everyone’s favorite seven stranded castaways through a fatuous storyline involving an ancient artifact, a world-destroying space alien and, as usual, an attempt at rescue botched by Gilligan.

Desert Stages artistic director Gerry Cullity had been trying to get permission to stage it since 2000, he says, but only recently has the Schwartz family begun to allow regional theaters to do the show. When Cullity got the nod late last year to premiere “Gilligan’s Island” in Arizona, he quickly slotted the show into the Desert Stages’ season in place of “George M!,” and set “Gilligan’s Island” for a run with no set closing date. Advance ticket sales have been strong.

“It’s just a testament,” he says, “to the fact that Baby Boomers are aging.”

Cullity took a lesson from last year’s hit production of “I Love You, You’re Perfect, Now Change” that was forced to close at his theater when a cast member dropped out sans understudy. For “Gilligan’s Island,” he’s rotating a mostly doubled cast. The only constant across both casts is Nick Lorenzini as hapless Gilligan.

An 18-year-old Scottsdale native who’s moved back to town recently after studying theater in California, Lorenzini admits he had to borrow DVDs of the show to see the original Gilligan in action. But like the other actors in the show — including Cullity, who’s playing one of two Mr. Howells — Lorenzini says he’s not doing an impersonation.

“I’ve just tried to take the foundation and go with my own thing,” he says.

There are two uncertainties in staging “Gilligan’s Island: The Musical,” Cullity admits.

The first is the soundtrack of Laurence and Hope Jubers’ grafted-on songs — catchy if dead-between-the- ears tunes with lines such as these, from the Skipper to Gilligan in “Shipwrecked”: “You’re the biggest knucklehead I’ve ever known/Everywhere you go becomes a danger zone.”

(Reached in Los Angeles, songwriter Laurence Juber offers, “If you’re expecting ‘Les Miz,’ it’s a different animal.”)

Then there is the fact that the Schwartzes’ liberal helping of sitcom jokes (Gilligan: “You know, Skipper, I’ve been thinking.” Skipper: “Well, there’s a first time for everything, Gilligan.”) are delivered without aid of that sitcom mainstay, the prerecorded laugh track.

Cullity expects audiences will be too busy enjoying their beloved “Gilligan’s Island” characters too much to be concerned with how strongly their funnybones are being tickled.

“There are so many things,” he says, “you watch and you get a nostalgia wave instead of thinking, you know, is it a laugh-a-minute.”

One thing’s for sure. Don’t expect any guest stars shoring up on this

“Gilligan’s Island.”

“Nope,” Cullity says, chuckling. “No Harlem Globetrotters.”