UNIVERSAL CITY, Calif. — Any attempt to do a comprehensive documentary about comedy in America in six hours would be doomed to failure because, well, it's just not possible.

Not that the producers of PBS's "Make 'Em Laugh" didn't try.

"In creating this six-hour history of comedy, we interviewed more than 90 comedians, writers, producers and historians, including Judd Apatow, Roseanne Barr, the Smothers Brothers, Carol Burnett, Sid Caesar, George Carlin, Larry David, Will Ferrell, Leonard Matlin Cheech Marin, Steve Martin, Chris Rock, Mort Saul, Dick Van Dyke and many, many others," said executive producer David Horn.

And it tries to give us a taste of about a century worth of comedy.

"This program starts with Charlie Chaplin and ends somewhere in the Jon Stewart world," said writer/director/producer Michael Kantor.

Unwittingly, Stewart helped inspire the production of "Make 'Em Laugh."

"In the fall of 2004, 'Make 'Em Laugh' was inspired by the presidential election," Kantor said. "It's true. The country was polarized, and the funniest comedy at the time, in my opinion, was 'The Daily Show's' 'Indecision 2004,' which made fun of both candidates."

And that made him think of doing for comedy what he did for the musical theater with his award-winning documentary series "Broadway: The American Musical."

"I began to think, just as … the Broadway musical was able to give insight into American history and the evolution of our culture, so, too, could comedy reflect American culture in all of its glory and weirdness," Kantor said.

Well, not ALL its glory and weirdness. Remember, it is only six hours. But it is just loaded with comedy legends and influences, some of whom are not exactly familiar to younger generations.

"My feeling was that people today don't know Jack Benny. It's really incredible," Kantor said. "So when we're making choices in terms of trying to figure out what to put in the series, it was always, 'Well, what's the amazing comedy that people don't know?' And when we're dealing with a comedy legend, 'What are the kind of clips that you can't rent at the corner video store?' "

"Make 'Em Laugh" is actually six one-hour episodes; two will air back-to-back on Wednesdays at 8 and 9 p.m. on Ch. 7 beginning this week. Each hour follows a different theme: "Would Ya Hit a Guy With Glasses? Nerds, Jerks & Oddballs"; "Honey, I'm Home! Breadwinners and Homemakers" on sitcoms; "Slip on a Banana Peel: The Knockabouts"; "When I'm Bad, I'm Better: The Groundbreakers"; "Never Give a Sucker an Even Break: The Wiseguys"; and "Sock it to Me? Satire and Parody."