We're continuing this periodic summer project where we revisit classic sitcom episode. Last week, we did a "NewsRadio" double feature, and today we're going to talk about one of my favorite episodes of "The Cosby Show," called "Theo's Holiday," coming up just as soon as my corporate headquarters has 49 floors but no phone...

Periodically throughout the latter half of the 20th century, various TV genres would be declared dead and buried. Some of them actually stayed dead, more or less, like the Western, while others lay fallow, waiting for the right show to bring the public mood back to it. In the early '80s, the sitcom was the genre being put out to pasture, falling behind dramas of various stripes, from the lofty ambitions of "Hill Street Blues" and "St. Elsewhere" to the soapy environs of "Dallas" and "Dynasty" to the comedy/drama/action mix of "Magnum, P.I." and "The A-Team." Then along came "The Cosby Show," which was an enormous hit — it single-handedly created the tradition of NBC dominating Thursday nights, which would continue for the next 20-odd years — and created new interest in the sitcom field among both audiences and network executives.

It was socially significant, too, in that it was the first sitcom with a predominantly (or, in this case, entirely) African-American cast where the conflicts weren't defined by race, or class. The Jeffersons, for instance, were well-to-do, but much of the comedy came from George butting heads with his honky neighbors, or from his blue-collar roots getting tangled up in his white-collar lifestyle. The Huxtables, on the other hand, were wealthy, functional, happy and admirable — the kind of family that not only other black families could aspire to (just as white audiences had once dreamed of being more like the Cleavers or the Nelsons), but that families of any race could want to be more like. This may sound insignificant now, or corny, but in 1984, this was a very big deal. "The Cosby Show" was a hit because it was funny, but also because people just loved that family, and the show played just as big a role in changing American attitudes about race as "Will & Grace" and "Ellen" would start changing attitudes about gay people in the late '90s.

The Short Version For Newbies: Bill Cosby is Heathcliff "Cliff" Huxtable, obstetrician, husband to attorney Clair (Phylicia Rashad) and father to kids Sondra (Sabrina Le Beauf), Denise (Lisa Bonet), Theo (Malcolm-Jamal Warner), Vanessa (Tempestt Bledsoe) and Rudy (Keshia Knight Pulliam). Sandra is off at college and appears sporadically in the early seasons (she's not in this episode, for instance), but the other kids are still living in the palatial Huxtable family brownstone in Brooklyn.

I've been watching "The Cosby Show" on Hulu with my kids as a way of weaning them off of the various Disney and Nick sitcoms they favor. It's from a period when most sitcoms were still designed as family-friendly viewing, and though the kids tend to favor episodes with a lot of Rudy in them (the slumber party episode with Peter and a young Alicia Keys is their favorite), they've come to love the antics of Cliff, Denise, Theo and the rest as well.

And as I've been watching it with them, I've gotten something of a crash course in classic sitcom storytelling values: not just the idea of the action centering around the living room couch, or the raucous (and, back then, mostly genuine) laughter from the studio audience, but the way that the show mostly told a single story per episode, favored very long scenes that allowed the Cos to be the Cos (or allowed the audience to simply bask in the warm glow of Huxtable land). Many other sitcoms of the era(*) tended to feature at least one subplot, if not more, which gave the whole ensemble something to do, kept the pace quick and kept the audience from growing tired of any one story. "The Cosby Show" writers didn't do that in the early days. They stuck with one plot, developed it as best as they could to fill a half-hour, and if the story didn't have much room for Denise or Vanessa or Theo one week, so be it. It's a harder discipline, but a potentially more rewarding one; "Everybody Loves Raymond" followed the same No Subplots credo, and Phil Rosenthal would talk about the challenges that created for the writers, but also noted that the payoff would be much bigger when they got it right.

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "The Revolution Was Televised," about the last 15 years of TV drama, is for sale at Amazon. He can be reached at sepinwall@hitfix.com