I recently posted about the show "Taxi" (see below). Another thing that occurred to me in watching the show again is how nearly plotless many if not most of the episodes are. Most sitcoms today tend to have plots; they may have super-complex plots like "Arrested Development," or fairly simple plots like a bunch of shows I can't really remember at the moment, but they all try to incorporate some element of twist-and-turn plotting, where the writer works to set up the problem and create some kind of unusual or interesting progression for how the problem gets resolved.
Many episodes of "Taxi" don't have any of that. Instead they set up a situation, and detail the amusing things that come out of that situation, and they end. They usually have a problem that gets resolved, but there are no real complications or twists involved in getting to the resolution; the structure tends to be that they spend act 1 setting up the problem, most of act 2 discussing the problem, and a resolution at the end. No twists, no structural games, no subplots.
For example, one of the best-known episodes of "Taxi" is "Reverend Jim: A Space Odyssey," the episode that introduced Jim as a regular. Written by the Charles Brothers and including the famous "What does a yellow light mean?" routine, it's one of the funniest sitcom episodes of all time. And it has essentially no plot at all. Here's a breakdown of the story beats in this episode:
Act 1: The cabbies meet Jim at Mario's (their hangout). They invite him to sit with them. He tells them his life story, filling in his background as the ultimate '60s burnout. The cabbies decide that they should help Jim get a job, and that since he has no skills or qualifications, the only job he could possibly get is cab driving. The entire first act is one continuous scene.
Act 2, scene 1: The cabbies ask Louie to give Jim a job. Louie refuses until Jim slips something into his drink that makes him feel very happy. Louie, Jim and the cabbies join in a chorus of "On Moonlight Bay."
Act 2, scene 2: Jim prepares to take the driving test. He spends most of the scene filling out his personal information ("Psychological problems or drug addiction?" "That's a tough choice"). At the tail end of the scene he starts the written portion of the test, and asks what a yellow light means. Then we dissolve to:
Act 2, scene 3: We find out that Jim passed the test. As a licensed cabbie, he gets his first cab and proceeds to drive it through the wall of the garage. The end.
So there is a problem, which is that Jim needs a job, and a resolution, which is that he gets it. But the problem doesn't take up much screen time, and the resolution occurs offscreen. Instead the 23 minute episode mostly uses the story idea as a hook for a character study of this very weird person. The time that could have been spent on extra plot twists or conflicts or unrelated "B" stories is instead spent allowing the scenes to run long, so the actors can have more time to do their stuff (the story goes that the "What does a yellow light mean" routine was much shorter in the original script, but director James Burrows allowed it to go on and on and on when it got a huge audience response). In many ways it's a script that would be thrown out of a screenwriting class, since it doesn't have much in the way of conflict, stretches out a thin plot and builds a nonexistent conflict to an almost nonexistent resolution. But it's a model of what good TV writing should be: something that is focused on character rather than plot, and considers the actors' opportunities as important as the writers'.