For the definition of a theatrical miracle, look at the phenomenon called "Nunsense," the tacky frolic that began Off Broadway 20 years ago and has become a cottage industry, a precursor to the "Sister Act" movies and a synonym for shameless commercial theater.

For the definition of a theatrical miracle, look at the phenomenon called “Nunsense,” the tacky frolic that began Off Broadway 20 years ago and has become a cottage industry, a precursor to the “Sister Act” movies and a synonym for shameless commercial theater. Spinning off five other shows, including holiday offering “Nuncrackers,” Jewish-centric version “Meshuggah-Nuns” and drag show “Nunsense A-Men,” the wimple juggernaut continues with this “all-star” 20th-anni edition. What next? “Nuns in Space”?

The milestone gives producers the chance to dust off the original version, cast some semi-familiar names and send it out on the road, where it continues to attract crowds beyond all reason. Writer-director Dan Goggin hasn’t altered the formula for this landmark version: It’s still marked by minimal production values, feeble songs and a corny old-joke book.

Premise has nuns forced to put on a talent show to raise funds in order to bury four sisters who are being kept in a freezer. They were the last victims in a food-poisoning accident by Sister Julia Child of God that nearly wiped out their order. The so-called talent show is a vaudevillian vehicle for nun-shtick, puns, parodies, puppets and some specialty numbers by the quintet of stars.

The cast assembled for this tour — Kay Ballard, Georgia Engel, Mimi Hines, Darlene Love and Lee Meriwether (with Deborah De Mastro and Bambi Jones understudying and otherwise filling out the seven-member order) — are game, but it’s often painful to watch their efforts to sustain life support in this flat-lining show. “C’mon folks, this isn’t easy,” says a weary Ballard after one of the oldest jokes in the biz — “How do you get down from a duck?” — lands with a thud.

No, it certainly isn’t. Even when references to thesps’ earlier careers — as Miss America (Meriwether), in TV’s “The Mothers-in-Law” (Ballard) and recording “She’s a Rebel” (Love) — are awkwardly inserted into the show, it’s with a desperation that is cringe-inducing.

Somehow this yuk-yuk sisterhood manages to show its talent despite the bad habits. Love is in fine voice; Hines displays her nightclub expertise with great audience rapport; Engel’s ditziness has sweetened with age; Meriwether is delightfully daffy; Ballard is the old pro who can land a laugh with a look.

But when Ballard says to the audience of a particular groan-producing lyric, “I don’t care if you like it. I love it,” she could be speaking about the show as well. For its fans, “Nunsense” is the theatrical equivalent of Bingo night: A ritualistic, formulaic, undemanding evening out. For others, of course, it’s pure hell.

Nunsense

Wilbur Theater, Boston; 1,195 seats; $66 top

Production

A Scott M. Robbins and Nunrun Prods. presentation of a musical in two acts, written and directed by Dan Goggin.

Creative

Sets, Barry Axtell; lighting, Paul Miller; sound, Ryan Powers; orchestrations, Michael Rice, David Nyberg; musical direction, Leo P. Carusone; production stage manager, Teri Gibson; musical staging and choreography, Felton Smith. Opened Feb. 10, 2004. Reviewed Feb. 13. Running time: 2 HOURS.

Cast

Sister Mary Regina - Kaye Ballard Sister Mary Leo - Georgia Engel Sister Mary Amnesia - Mimi Hines Sister Mary Hubert - Darlene Love Sister Robert Anne - Lee Meriwether Sister Mary Luke - Deborah Del Mastro Sister Mary Brendan - Bambi Jones
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