Though the faces and places have changed, the stoner comedy template hasn’t altered much in the past 30 years. The best ones require two things: lots of smoking, and an impossible trek to complete. Whether it’s halting studio production of “Bluntman and Chronic” (“Jay and Silent Bob Strike Back”), or just heading to White Castle, the fun is in the journey, not the destination.
So while “Tenacious D in The Pick of Destiny” might not be the most original movie, JB and KG will rock harder than Harold and Kumar every time.

The film opens with a parody of George Lucas’ “THX,” changed to read “THC: The audience is now baking.” After that, the film rarely lets the viewers forget they are indeed watching a stoner comedy. But “The Pick of Destiny” wouldn’t be that funny if the whole movie was anything other than pot humor.

Part “Spinal Tap,” part “Indiana Jones and the Last Crusade,” “The Pick of Destiny” is the story of the “world’s greatest rock band” and its quest to obtain the fabled Pick of Destiny. The P.O.D. is the holy grail of rock, a mysterious guitar pick whose Satanic powers have influenced all the great guitar gods of rock. Can Jables (Jack Black, lead singer and guitarist of Tenacious D) and Rage Kage (Kyle Gass, backup singer and guitarist) discover the pick and achieve their destiny, or will hell’s grim tyrant reclaim his awesome pick?

Even though the climax ultimately fails to live up to its own buildup, Black and Gass prove surprisingly deft at leading the audience on an entertaining ride. They first became the D nearly a decade ago, and, though “The Pick of Destiny” is its first theatrical outing, the duo has worked wonders in a variety of media already. Along with short films and a defunked television series for HBO, the D released one of the greatest albums of this decade: 2001’s “Tenacious D.” The soundtrack for “The Pick of Destiny” marks the group’s first new studio material in five years.

“The Pick of Destiny” is essentially a musical, so fans who listened to the album weeks before the film came out may be surprised to see about one-third of the movie already on sale in auditory form. Still, some of the most hilarious moments of the film are musical moments. “The Pick of Destiny” features a show-stopping “Bohemian Rhapsody”–style intro, complemented by cameos from Meatloaf and Mr. Ronny James Dio. Pining about being stuck in the monotony of the suburbs, Black channels his inner Freddie Mercury and Bon Scott simultaneously.

Combining their musical abilities and comedy styles, Black and Gass have accomplished a rare feat with this film. They stretched a concept from small, tightly choreographed musical skits into a feature– length film, without boring their audience to death.

The credit here goes largely to Black, who in the past five years has surpassed his guitar whiz bandmate KG to become a fairly mainstream comedy star. This is partly because all of Black’s hilarious personas in comedies like “High Fidelity” and “School of Rock” stem from the same character: JB (aka Jables). Though he also starred in Peter Jackson’s epic “King Kong,” Black is most magnetic in his home element. He and Gass not only rock but also shine as a comedy duo.

Black and Gass could have tried to cash in and mainstream their bumbling rock creation. Instead, they created a comedy that is hilarious and accessible but still a complete love letter to longtime fans. And something like that only happens “once every 100,000 years or so, when the sun doth shine and the moon doth glow. And the grass doth grow.”

“Tenacious D in The Pick of Destiny” was written by Jack Black and Kyle Gass and directed by Liam Lynch.

“The Pick of Destiny” received three stars.