FILM : Watching Spinal Tap Hit Rock’s Bottom

“This Is Spinal Tap” is a sobering documentary about the history of a rock group that never quite made it. This probing, demanding exploration is the perfect companion to Martin Scorsese’s optimistic homage to the Band’s final concert, “The Last Waltz.”

Nah, just kidding.

Actually, Rob Reiner’s 1984 movie (screening at UC Irvine Friday night) is a bull’s-eye parody of the rock lifestyle, the pop music business machine and the affectations of cinema verite . What makes it so funny is how deadpan Reiner and his cast approaches the whole scenario. He follows the fictional Spinal Tap, a band that once had a hit album called “Listen to the Flower People” during the ‘60s, on an increasingly degrading and volatile tour that eventually reaches the depths of amusement parks and military bases.

Having evolved into a scream-singing heavy-metal band (they favor tunes like “Smell the Glove” and albums with names like “Intravenous de Milo” and “Shark Sandwich”), Spinal Tap endures one indignity after another on this last-gasp trip. As the tour progresses, the audiences get smaller, the venues crummier, the hotels dumpier and the tempers hotter. Spinal Tap disintegrates before us.

Reiner apes the standard documentary techniques unerringly, giving “This Is Spinal Tap” a cockeyed reality that makes the humor so well aimed. Like most documentaries, this one has a narrator, the slightly off but self-important Marty DiBergi, played by Reiner himself.

DiBergi first recounts the group’s checkered history. He tells us how he discovered Spinal Tap in a tiny Greenwich Village club called the Electric Banana, where they impressed everybody not only for their loud musicianship but unusual punctuality. A few years later, they’d come up with their seminal song, “Sex Farm.”

But that was awhile ago. Spinal Tap still has fans, but not many of them. Even bandleader and lead guitarist Nigel Tufnel (Christopher Guest) concedes that the group’s appeal has grown selective over the years. Tufnel, like the other Spinal Tappers (Harry Shearer and Michael McKean, both hilarious, as is Guest), answer DiBergi’s soft questions with a pseudo-thoughtfulness, always taking a serious approach to a ludicrous situation.

They can’t even see their own demise written on the billboard at the Themeland Amusement Park where they’re suppose to perform. The band is listed, in much smaller letters, as the second act behind some sort of puppet show.

“This is Spinal Tap” is such a gas that it feels a little silly to dwell on the satirical points Reiner and fellow screenwriters Guest, McKean and Shearer are making about pop star isolation and the fickle nature of celebrity. But they’re there, amid all the preening and off-key guitar riffs.

What: Rob Reiner’s “This Is Spinal Tap.”

When: Friday, May 3, at 7 and 9 p.m.

Where: UC Irvine’s Student Center Crystal Cove Auditorium.

Whereabouts: Take the San Diego (405) Freeway to Jamboree Road and head south. Go east on Campus Drive to Bridge Road. Take Bridge Road into the campus.

Wherewithal: $4.

Where to Call: (714) 865-6379.