Fire up the fondue and unpack the pet rock, the '70s just keep coming back. The disco decade is catnip for Hollywood. Like Classic Rock, it just never goes away.

With the new Will Ferrell comedy, "Anchorman," opening nationwide this weekend, moviegoers can return to an age when chest hair mattered.

"Anchorman" is just the latest go-around to plumb the dumbed-down '70s for sight gags and cultural yuks. The decade has become a national plaything for post-boomer writers and actors. Tube socks and bong hits. It's a safe place to go (as long as you leave out Watergate, the energy crisis, the embassy rooftop in Saigon and Billy Carter).

"The '70s have built-in humor. You got the guy in the big Afro, you have the bell-bottoms. Man, the audience is starting to smile. They're already halfway there," waiting for the punch line, says Fred Wolf, screenwriter of "Joe Dirt" (mullet-wearing metalhead reject David Spade, trapped in the '70s) and "Dickie Roberts: Former Child Star" (circa '70s kiddie actor David Spade reliving his childhood in the '90s).

Wolf adds another reason that the '70s are such a fat target. "They don't have the '60s idealism. It's hedonism stripped of meaning. There's no seriousness to it. It's the hanging-out generation."

If the '70s are a stock for comedy, though, it might be time to think about selling. The past few seasons have been a conveyor belt spewing forth movie remakes of '70s television series: "Charlie's Angels" (flippy-dippy Farrah Fawcett hair wings for Cameron Diaz), "Scooby-Doo" (stoner references for cartoon dog with serious munchies) and "Starsky & Hutch," the Ben Stiller/Owen Wilson replay that features a disco inferno dance contest right out of "Saturday Night Fever." Hollywood can't resist a pair of white shoes and an eight-track.

Coming soon: "The Dukes of Hazzard."

One screenwriter joked that this trend leads, inexorably, to "Diff'rent Strokes: The Gary Coleman Movie."

Even comedies with contemporary settings have been tapping into characters and references designed to quote the '70s -- like the male model Derek in "Zoolander" and the infamous zipper scene for poor Ted on prom night in "There's Something About Mary." Stiller seems to have found his muse.

And there have been movie remakes of '70s comedies. For, truly, what is "Old School" (Ferrell again) but "Animal House" redux, a nostalgic college kegger for the ages?

Same for the gags in "Undercover Brother" (Eddie Griffin, Chris Kattan) and "The Ladies Man" (Tim Meadows), which both spoof the blaxploitation pics of the '70s.

Whom do we have to thank for this?

The staff of "Saturday Night Live," that's who. They dominate the roles or screenwriting credits for nearly all of the above. It appears that at some crucial moment in their development of a sense of humor (and some of them were children in 1975; Ferrell was born in 1967), they were watching Steve Martin and Dan Aykroyd play the wild and crazy guys. It stuck, like a burnt orange polyester leisure suit on a hot afternoon.

This is not necessarily a bad thing. Yes, there are real dogs in this kennel. But some moments in "Zoolander" are irresistible. "Something About Mary" sparked a host of Farrelly brothers impersonators.

At the premiere of "Anchorman," the audience was enjoying the joke. You watch the action news team strut across a park and flip the leftover trash from their lunch onto the grass (once upon a time, we were a littering nation), and you may laugh. Simpler times. And when they break into a harmonic rendition of the Starland Vocal Band's pop anthem "Afternoon Delight," you remind yourself: That song -- "Rubbin' sticks and stones together make the sparks ignite" -- was Billboard's No. 1 hit on July 10, 1976. Can't deny it, people. It's our national gold chains, rattling in the attic.

Pre-AIDS: Ferrell's character, Ron Burgundy, could stage an orgy. He could wear red underwear and do cannonballs in the party pool and slur, "Scotchy, Scotchy, Scotch, I love Scotch."

When one of his newsroom pals decides to hit on Veronica Corningstone (Christina Applegate), who is trying to break into the all-male world of TV news, he says: "Time to musk up." Ferrell's Ron Burgundy tries his own pickup line but fumbles it: "I want to be on you." When the news director informs them that the times are a-changing, and Ms. Corningstone will ascend to the anchor desk, one of the team complains, "What in the hell is diversity?" Ron Burgundy answers with authority, "An old wooden ship used during the Civil War."

His name, too, is perfect in pitch. Adam McKay, former "SNL" head writer and co-writer of the "Anchorman" screenplay with Ferrell, says the duo spent two days struggling to come up with the name of the anchorman.

"We can't write until we have the name," says McKay, lounging on a sofa at a Santa Monica beach hotel, riffing on the decade and its humor potential and pitfalls. They thought about "Ted" but rejected it because of Ted Baxter, the ridiculous newsman on "The Mary Tyler Moore Show." So they instead named the dog in the movie Baxter. Don was a possible. But then they hit on Ron. Bingo. At first it was "Ron Nightingale," but then Ferrell whispered "Burgundy," and they knew they had the joke.

The filmmakers explain that the genre works because the '70s, or at least the lampooned version, feel ridiculous today, in a way that the '80s are not (yet). The Happy Days of the '50s are too far away for today's teen-twenty demographic; the '90s too close; the '60s too intense.

"The '70s are fun for me -- they're the '60s without the drama. They feel free and unrepressed, and you can do anything outlandish," says John O'Brien, an "SNL" veteran and one of the screenwriters of "Starsky."

Plus, "there's the cyclical nature of what's hip. There was a time the '70s were the least cool thing on the planet." Now, he adds, "Tight jeans and platforms are back."

McKay says he and Ferrell were initially feeling shy about a rewind. "We actually didn't want to do the '70s," he says. "It's been played hard. The decade has been so mined." McKay says they went with the '70s because it allowed them to do riffs on the rise of "women's libbers" assaulting the all-male citadel of local TV news. Plus, TV news itself has moved deeply into self-parody. Panda Watch at 6!

McKay, who is 36, says his touchstones for comedy come from the '70s: the early years of "SNL," the movies "Airplane!" (sad to think of its shabby current remake "Soul Plane") and "Blazing Saddles," the kind of "smart dumb humor" refined to art by "The Simpsons."

Moviegoers have their own '70s replay lists. Some of the critical favorites to do the decade right are Richard Linklater's "Dazed and Confused" (1993), Cameron Crowe's "Almost Famous" (2000) and, looming over all, Rob Reiner's "This Is Spinal Tap," made waaaay back in 1984.

So, it is true. Everything old is new again.

Will Ferrell's "Anchorman" is the latest film to lampoon the '70s. Many star "Saturday Night Live" cast members.

Matthew Lillard and friend have a '70s flashback in "Scooby-Doo."