When Anvil opens for AC/DC in Boston and New Jersey this week, it will be no small triumph for a once-forgotten Toronto heavy metal band that has spent the past 25 years angling for another shot at the big time.

But these gigs represent something else, too: the latest development in a saga that has extended far beyond the silver screens showing 'Anvil! The Story of Anvil,' Sacha Gervasi's acclaimed documentary about the group's trials and tribulations.

Released across North America this past spring, the film's real-life underdog tale upended the clichés viewers expect from movies about music, especially when they're about the people who play its heaviest variety.

Like another recent metal doc with a Canadian connection -- 'Flight 666,' a revealing portrait of Iron Maiden on tour by Toronto-based directors Sam Dunn and Scot McFadyen -- 'Anvil!' avoids the salacious, scandal-first template set by VH1's 'Behind the Music' and refuses to follow the reality-TV route to mock them as still-at-it has-beens. Instead, these Canuck-influenced music docs offer a more human, realistic and celebratory salute to those about to rock.

Since the film's premiere at Sundance 2008, Anvil's string of triumphs comprise one of the most unexpected music stories in recent memory. Even so, Anvil singer Steve "Lips" Kudrow says he saw it all coming. "No one else believed me, including Sasha," he tells Spinner during a recording session break. "He was telling me, 'Slow down your horses, man, take it easy.' I said, 'No, it's going to be the biggest thing since sliced bread.'"

While not quite putting bakeries out of business, 'Anvil! The Story of Anvil' has had an inordinately large impact for a no-budget indie doc about aging Canadian metallers slogging their way through the ass-end of the music world decades after missing their big break. With cinema releases still to come in Japan and Australia, VH1 is bringing the film to TV and DVD this fall, as well as reissuing Anvil's latest album, 'This Is Thirteen.'

VH1 is also sponsoring the Anvil Experience, a tour combining movie screenings with live performances. Kudrow says it was always Gervasi's intention to use his film as a vehicle to promote the band as a going concern rather than a historical subject. Anvil's frontman believes this creates a unique opportunity for moviegoers.

"Since we were all little kids, our parents have told us, 'It's only a movie, it's only a movie.' So you go into a movie theatre with the mindset that it's all make-believe. But as you watch this movie, you start to realize that it's real -- the ultimate proof is we come out onstage! The other thing that is quite unusual about this situation is that people in the audience have a position in helping the band. By buying a CD and buying a T-shirt, you are affecting a real story. You are helping create an epilogue."

Kudrow chalks the AC/DC offer up to Angus Young becoming one of countless moviegoers who have joined Anvil's cause. Despite the hardships the film depicts, Kudrow says, "People see that we have not given in and you don't pity people who haven't given in -- you admire them!"

Speaking from the perspective of a diehard metal-head, director Sam Dunn says Kudrow has long had the makings of a movie star. "If one guy was built for the camera, it's him," Dunn notes from the Toronto office of Banger Films, makers of 'Metal: A Headbanger's Journey,' 'Global Metal' and 'Flight 666.'

Happy to see one of Canada's most enduring metal institutions get its due, Dunn and McFadyen are also working on a career-spanning doc about Canada's most revered contributor to the genre, Rush. In the meantime, they're soaking up the goodwill created by 'Flight 666' -- one of the year's best-selling music DVDs, it hit No. 1 on five continents.

It depicts the physically demanding but surprisingly cheerful travels of Iron Maiden as the British metal legends toured with family and crew aboard a Boeing 757 flown by Bruce Dickinson himself. Though 'Flight 666' portrays a band that achieved the massive international success that's thus far eluded Anvil, it similarly disproves the usual rock'n'roll boilerplate when the men of Iron Maiden turn out to be a friendly bunch of blokes.

"We were surprised by just how down to earth these guys are," says Dunn. "They have families, they play sports, they like to have a good time but they are not the rock 'n' roll casualties that we have been conditioned to expect through reality TV. It's really a story of a rock band that was smart and took care of themselves and now to their surprise are benefiting from that, playing some of the largest concerts in the world."

That makes for an unusual film, and a welcome one considering the most prominent representations of metallers in the media are found in Bret Michaels dating shows and Ozzy Osbourne ads. Surely metal fans deserve a more thoughtful and realistic treatment of their world.

"The 'Behind the Music' template has become the grand narrative of what is supposed to happen when you are in a rock band," says Dunn. "What we are doing with our films is showing that you don't have to be just a young kid in spandex with a bandana to be able to play great metal music. And you can get better with age, like a fine wine."

What's more, 'Flight 666' and 'Anvil! The Story of Anvil' may be exposing metal's true mettle to moviegoers who've never known the pleasure of owning a studded wristband.

"That's where it breaks down a lot of barriers that most movies or most metal bands would never have dreamed of," says Kudrow. "Playing at the Egyptian Theatre at the premiere in LA, looking out at the audience was like looking at the front cover of 'Sgt. Pepper's only it was real!

"Seeing Dustin Hoffman on his feet doing the devil horns and singing 'Metal on Metal' says volumes about what is going on here."

Anvil play with AC/DC July 28 at Gillette Stadium in Foxborough, Mass., and July 31 at Giants Stadium in East Rutherford, N.J.