I was too young for the first run of the Dick Van Dyke Show and remember practically nothing from the re-runs except Dick either falling over or side-stepping the ottoman, but boy do I remember the no thumbs episode!
Of all the episodes, the only ones I remember are the aliens and Laura getting her toe stuck in the tub faucet (I was playing with a drip!). And I watched that show a lot.
Buffy - I loved “Once More, With Feeling”, but “Hush” was amazing, and both scary and funny (more like the series)
Fresh Prince- the one with Will’s Dad
Different Strokes- the one with the bike shop, or when Arnold and Kimberly get kidnapped
My favorite for gay farce on the show would be when Martin fakes being gay to let a woman down easy, then winds up on a date with a man. “You couldn’t tell he was gay?” “He’s British - they all seem gay to me!” The scene where Niles breaks up with him is hilarious.
Don’t toy with me, you saucy wench! 
Ah, yes. It’s always the young ones. 
“Doughnuts”?!? What’s a “doughnut”???
It’s the musical episode of the show.
Speaking of which, most memorable episode of The Young Ones, “Bambi”, the one where the boys appear on “University Challenge”.
As far as Dick Van Dyke (or as I refer to him on sites with heavy censorship programs, Manpart Van Lesbian) goes, I think that a lot of people also remember the “baby switching” episode. (The big gag was that the family with which Dick thinks that his baby was switched was black.)
And as for ABC Movie of the Week, they did so many “Pilots” on that franchise that singling out “Trilogy of Terror”, memorable as it was, seems off the mark. The “Night Stalker” pilot would be my choice: “This nut THINKS he’s a VAMPIRE!!! He’s killed four, maybe five women. And THAT is NEWS, Mister Vinchenzo. We are a NEWSPAPER, we’re supposed to PRINT the news, not SUPPRESS it.” (That was from memory.)
Technically, it wasn’t a pilot. Yes, it was an ABC Tuesday Movie of the Week and it was based on a novel by Jeff Rice called “The Kolchak Papers” (I still have my paperback copy). The ratings were so good they made a second movie, “The Night Strangler”.
Thanks to the popularity of both films they made a (short lived) TV series.
NBC’s Experiment in Television during the late 1960s. Only one episode of it really stood out in my memory and it eventually turned out in a lot of people’s memories to be legendary: Jim Henson’s surreal TV play The Cube, which aired in February 1969. The next time I tuned in, all I can remember is a play with a character named Ishmael confronting earth, water, air, and fire on some quest, but otherwise it failed to impress and is probably forgotten.
Oh dear, it’s raining again.
For “The Odd Couple” I would suggest the episode where Oscar is mistakenly arrested for ticket-scalping, with Felix’s famous line, “When you ASSUME, you make an ASS out of U and ME!”
Another would be the one with the flashback to Oscar and Blanche and Felix and Gloria’s Caribbean vacation, in which Felix sings a Calypso song with the chorus “Oscar, Oscar, AH-AH-AH-AH-AAAAAH!”
One word, Aristophanes!
Futurama:
Jurassic Bark
Amazon Women in the Mood
Happy Days: the one with Mork.
Northern Exposure: the one with the frozen mammoth.
Good Times: the one where whoishisface dies. (Daym, daym daym!)
The Beverly Hillbillies: the one where Granny fights the kangaroo. (Or the one where Granny rides the ostrich.)
Angel: Smile Time.
(A slight derail, but I’d probably go with “the one with The Scum of the Earth” as the second-most familiar WKRP.)
Several mentions of various The Dick Van Dyke Show episodes. But to me the most memorable is the one where they found out they weren’t legally married because Laura had lied about her age.
That and the one were Buddy insults Mel.
People remember the finale, but they don’t call it that. They’ll get real quiet and then say, “The one on the bus, with the chicken.”
Seinfeld - I’m dithering. It’s either “The Soup Nazi” or “Spongeworthy” and I’m thinking it may by gender specific. . .
General Hospital - Luke and Laura on the island. . . with Rick Springfield. I still can’t believe the show survived that steaming pile of crap.
The Electric Company - The “-ly” Song.
The one where somebody shot JR
The Love Boat - Charo’s first visit.
Another **Frasier **show.
The one where they decide to restage a classic 50’s Radio Mystery play
The second half had me laughing so much I got everybody in the house, I was house-sharing with some fellow 20-somethings at the time to come down and watch the repeat that was shown a couple of hours later.