NEW YORK – Platform shoes, leisure suits, fondue, fro picks. What used to be cool is now the stuff of comedy.

When it comes to period comedies, the ’70s are the equivalent of Victorian era costume drama. While serious-minded filmmakers are forever reaching back to the time of royalty clad in waistcoats and dressing gowns, comedians are more likely to cull from the less halcyon days of disco and sideburns.

Will Ferrell is again mining the decade with “Semi-Pro,” a movie in theaters Friday about a fictional ABA basketball team, otherwise realistically set in the ’70s. Ferrell earlier traveled back to the “Me Decade” for 2004’s “Anchorman: The Legend of Ron Burgundy.”

“Whenever I look back at old photos and this and that, it just seems like such an alien time,” Ferrell said. “The ’80s are funny too, and I guess we’ll look back and the ’90s will be funny too, but the ’70s are holding strong.”

Ferrell is far from alone. In 2004’s “Starsky & Hutch,” Ben Stiller and Owen Wilson returned to when a Ford Gran Torino could be an object of obsessive pride. Cameron Crowe’s “Almost Famous” (2000) captured the ’70s – like many films set in the decade – through music.

“I’m Gonna Git You Sucka” (1988) parodied ’70s blaxploitation movies, ground eventually covered in the ’60s-oriented “Austin Powers” films, specifically the third installment: “Austin Powers in Goldmember” (2002).

On the tube, the eight seasons of “That ’70s Show” proved far more successful than its spinoff, “That ’80s Show,” which lasted for just a season. Though it takes place in 1980 and 1981, the cult classic series “Freak and Geeks” was largely imbued with ’70s culture, like laser light shows and proms with Styx blaring.

“The danger with any period piece, especially of a more recent history, is that it can become cartoony really fast,” said “Freaks and Geeks” creator Paul Feig, 45. “The biggest thing on ‘Freaks and Geeks’ was monitoring up front the costumes and all that. A show like ‘That ’70s Show’ is clearly making fun of those archetypes – and that’s fine, that works for that show – but it was a big thing for me to go like, ‘No, everyone did not wear leisure suits.'”

Even without the period cliches, the particular vibe of the ’70s is especially suited to comedy. If the decades are characterized stereotypically, the ’50s were uptight and fearful, the ’60s were turbulent and optimistic, and the ’80s were crass and commercial. The mood of the ’70s is often viewed as a period of cynicism and languor: both innate qualities of comedy.

“Anchorman” director Adam McKay recalls the ’70s as a “very bipolar decade” of grim reality and rich fantasy. Vietnam ended in failure, recession and gas shortages spread across the country and Watts exploded in violence – all while disco ruled the airwaves and drug-fueled parties raged.

“The reality of the change of the ’60s was coming into place, and a lot of the time, it was pretty funny,” said McKay. “The ’60s were what legitimately brought in a lot of social change, but the ’70s is when some of it seeped into the actual day-to-day living patterns of most Americans.”

In Richard Linklater’s 1993 classic, “Dazed and Confused,” the red-haired character Cynthia Dunn (Marissa Ribisi) explores the “every-other-decade theory” on the last day of school in 1976:

“The fifties were boring. The sixties rocked. And the seventies, oh my God, they obviously suck. Come on! Maybe the eighties will be radical.”

In an essay, film critic Kent Jones praised “Dazed and Confused” for achieving an accurate “balance between the aggressive and the dreamy” particular to “this odd, floating moment in history, when all decisive gestures seemed strange and suspect.”

“There was a melancholy feel to the ’70s,” said the 40-year-old Ferrell, who nevertheless remembers them fondly. “I was so into the bicentennial. No joke. I bought a Liberty Bell necklace that was pewter. It was like a prized possession.”

Paul Thomas Anderson’s “Boogie Nights” (1997) was ultimately a drama, but took much of its comedy from depicting outlandish aspects in the ’70s pornography industry. You have Rollergirl (Heather Graham), a kung-fu fanatic (Mark Wahlberg) and a director (Burt Reynolds) worried by a new medium: videotape.

The period details in “Semi-Pro” are considerable: Evel Knievel-style stunts, medallions slung over turtlenecks, tri-colored basketballs and, of course, the expression “jive turkey.”

“If it feels like there’s a fun way to comment, you find those little moments, otherwise it should fit in the texture of the film,” said Ferrell.

In “Anchorman,” Ferrell’s newsman character, Ron Burgundy, memorably discovers a “new fad”: “I believe it’s jogging or yogging. It might be a soft ‘J.’ I’m not sure but apparently you just run for an extended period of time. It’s supposed to be wild.”

McKay, 39, believes ’70s-set comedies remain relevant because of a universal theme of old meeting new – albeit a “new” often ridiculously dressed and grooving to Rush.

“What’s the common thread in all of them? In ‘Dazed and Confused’ the quarterback has the conflict with the old-school football coach,” said McKay. “In (‘Semi-Pro’) it’s the ABA verse the uptight NBA. And in ‘Anchorman,’ you have the new sharp woman journalist against the old guard.”

That films set in the ’70s continue to proliferate isn’t just a coincidence; that’s when many of the comedians now currently dominating the scene came of age. It’s only natural they would return to what all comedians perpetually contemplate: adolescence.

“I was just starting to have my opinion about what I thought was funny, and trying to be funny,” recalled Ferrell. “All those things were happening around that period of time.”

McKay, who was reluctant to make “Anchorman” in the ’70s because it had been done before, is amazed the ’70s – skipped over by everyone else – continue to be such fertile ground for comedians.

“I was shocked to see that it’s still continuing,” he said. “It’s turned out to be a really deep well.”