This has probably been done before, but it’s still fun.
I’ll start.
The X-Files - Clyde Bruckman’s Final Repose.
Great story, great acting. Funny, creepy and poignant.
Next?
Blackadder
Blackadder the Third: Ink and Incapability.
Johnson, Shelley, Byron and Coleridge, all taken the piss out of.
Nice.
Firefly - Objects in Space
Great guest villain, gripping plot, great dialogue.
In interviews, Wheden talks about the ship being a character all it’s own. That’s true in this episode on multiple levels. Wonderful camerawork.
Mystery Science Theatre 3000: Space Mutiny
Thick McRunFast!
Buff Drinklots!
Gristle McThornbody!
Dirk Hardpec!
Punk Rockgroin!
Slab Bulkhead!
Big McLargeHuge!
All Star Trek
ST:TNG - Starship Mine
ST:ENT - Cogenitor
ST:VOY - Year Of Hell (I&II)
ST:TOS - Assignment: Earth
ST:TAS - The Slaver Weapon
ST:DS9 - In the Pale Moonlight
Movies - First Contact
Will have to think about Doctor Who eps for a while, but off the top of my head…
Nu-Who: 1st! - Blink — 2nd -Dinosaurs! On a Space Ship!
Old Who: Robots of Death - Horror of Fangrock
[singing] He TRIED to kill me with a forklift!
Twin Peaks: Pilot
X-Files: Jose Chung’s from Outer Space
Futurama: Jurassic Bark
Simpsons: Homer and Apu
The Wire: Middle Ground
Mad About You: The Finale
Six Feet Under: The Finale
Northern Exposure:
The episode where Chris can’t vote and they hold an election
The episode where Shelly attempts to duplicate the taste of very expensive wine
The episode where Fleishman’s uncle dies and he says Kaddish in front of everyone else
The episode where they show how Cicely was founded
Basically any episode of the show before the Bubble Jerk pops in.
WKRP: The turkey episode.
Taxi: Jim takes the hack license test.
Doctor lady.
Chefguy-What…does…the…yellow…light…mean?
My preferred genre of Television is comedy, and these episodes are worthy of the stage.
Dick Van Dyke Show – It may look like a walnut (The Planet Twilow?)
Taxi – Reverend Jim’s inheritance (Jim’s dad dies and leaves him a suit and a Stevie Wonder song)
Mary Tyler Moore Show – Chuckles Bites the Dust (Chuckles dresses as a peanut to lead the circus parade, and gets trampled by elephants.
Cheers – Pick A Con, Any Con (Harry Anderson, as a con man, helps Coach swindle his swindlers)
Frasier – The Two Mrs. Cranes (Daphne’s old boyfriend comes to visit, and she wants nothing to do with him, so she gets Niles to pretend he’s her husband named “Frasier”, when Roz shows up she pretends to be Maris, which makes Frasier pretend to be Niles…
MST3K - The Mole People A 50s movie with John Agar, Hugh Beaumont (Ward from Leave it to Beaver, and Alan Napier (Alfred the Butler from Batman)* “It’s baby Jessica! She’s digging her own way out!”* and lots of Ward Cleaver jokes.
Great show, and the Episode where Ed dubs the Prisoner of Zenda into some Aleut language is hilarious (“Hey, don’t tell me what to do, I used to work with Jay Silverheels”) but also transcendent when the finished product is screened.
WKRP… “As god is my witness I thought turkeys could fly.”
Taxi…
“What does yellow mean?”
“Slow down.”
“Wh…a…t, d…oes, ye…ll…ow m…ean?”
both excellent picks.
BtVS - Hush – Creepy bad guys and almost zero dialogue, plus hilarious sight gags.
Angel - Smile Time – Atypical but fall-on-the-floor funny.
Really? Horror of Fang Rock? The spouse and I couldn’t even sit through all of that, it was so slow. Different strokes, though 
Mork and Mindy: The first time he meets Exidor (the “Friends of Venus” episode)
Frasier: Flour Child
Doctor Who: Blink
House: Three Stories
Breaking Bad: Ozymandias
The Simpsons: Cape Feare
Futurama: Roswell That Ends Well
Overdrawn at the Memory Bank is also a great choice.
Agree, although Clyde Bruckman is also amazing.
One of my favorites! This is a nice, somewhat under-the-radar choice.
Yes.
That’s from Fugitive Alien, which is also hilarious.
I held off on posting because I couldn’t decide between these two episodes.