Firefly, Mal’s sword fight and its merciful ending 
**1: Oz **- the scene in the premiere episode of Schillinger slowly burning a swastika brand onto Beecher’s ass-cheek with a butane lighter and a heated ballpoint pen.
2: The Twilight Zone - either little Anthony making that poor sonofabitch Dan into a horrific jack-in-a-box at his own birthday party, or…
“I’m Talky Tina, and you’d better be real nice to me.”
3: Dragnet- the look of self righteous disgust and disdain on Joe Friday’s face as he tells off the hippie college professor who dared question his stance on the unremittant evil of psychedelic drugs.
4: Night Gallery - the end of that one episode, where the guy opens up the box and there’s this *doll *in there, that opens its eyes and smiles at him…aaaaiiieeee!
5: Law and Order when a guy says, with a straight face, “I perform fellatio on my wife.”
6: Jonny Quest-Turu the Terrible Pteranodon, felled by a bazooka shot, plunges into a tar pit – and the madman in a wheelchair who’s been keeping the monster as a pet dives in trying to save him.
7: Friday the 13th, The Series - one of two moments in the first of the episodes involving the cursed compact mirror. Either the beginning when its possessor (an ugly, demented little bag-lady) uses it to lure a yuppie stud to a horrible end, or later on when the ugly, hateful but still pitiful high school girl who discovers the same mirror later on, comes into the room all dressed up for her prom date.
8: the moment on Soap when Jody’s mom walks in on him in full drag, dancing around his room and singing “I Enjoy Being A Girl!”
9: Whenever Lucy goes "AAAAAAAAAUUUUUUWWWWWWWWWHHHH!!!"
Which just brought to mind in the episode of the origin of Cicely, Chris, instead of just couting to three, says “Now I’m going to recite the three points of Hegelian Dialectic and then you’re coming with me. Thesis. Antithesis. Synthesis.”
Crap … that show was too intelligent for it’s own good.
I don’t know if it was the same episode, but the defining moment for me was the young couple breaking down when they discovered their child floating in the bathroom after having spent the night taking drugs. And Bill Gannon’s reaction.
Veronica Mars, narration of the very first episode:
“Quite the reputation I’ve got, huh? You wanna know how I lost my virginity?
So do I.”
Frasier - Niles is living in an apartment way to big and expensive for him (during or post divorce). Martin (dad) is on the intercom. . .lost in a room with lots of rolls of paper. “That’s the gift-wrapping room, Dad”. (Cracks me up to think of it everytime!)
MASH - Major Burns gets flustered after a compliment and says “It’s nice to be nice. . .to the nice”
MONK - A pot field is burning. Monk is inhaling (but doesn’t want to) and ties himself to a post of some sort. He’s freaking out and saying “OMG. I’ve got the reefer madness!” Another character is watching this whole thing and says something like “I’ve had some experience in this area, and I don’t believe you are high”. THAT was one of the funniest scenes EVER!!
ST: TNG: The scene where Picard is standing at the window in his quarters, playing the ocarina, right after he comes back from his virtual life. (Well, and Frere Jacques. 
)
Firefly: Kaylee with the parasol and hair buns right spang in the middle of a bustling Chinese openair market.
Sports Night: Dan’s apology in ‘The Apology’.
Gargoyles: When Demona and Goliath hug, before it all began…
Supernatural: I’ve only seen S1 so I’ll have to go with, “Hold me, that was beautiful.” (I have S2 on my table at home, I swear…) For me, that pretty much sums up Dean.
WKRP - The station manager has just found out the foot powder he’d just applied was actually a bag of cocaine brought to bribe Fever. There’s a slowly rising terror in his eyes and he begins to run around in panic, sure he’s about to become an addict, screaming “I’ve got a monkey on my foot!”
For Seinfeld I always think of the Naked body suit episode when George tries to get fired.
For Friends I normally think of the episode when Joey moves out into his own apartment…so sad.
That was CSI: Vegas, actually.
For Seinfeld, it’s *The Bet * episode.
For me, it will always be the scene from the episode “Future Tense,” where:
Broadway dies. Ok, he doesn’t really die, since it’s a fake reality, but still…very well done.
V. Diana swallows a live mouse.
I was 10 years old, it took me weeks to recover from the shock, and it’s stayed with me ever since.
Was it a mouse?
I remember it as a canary.
The mind fades… 
I’ll try and come up with a few that haven’t been mentioned.
Frasier Upset at the advice a “tough love” therapist is giving out, Frasier reunites her with her estranged mother, who turns out to be a complete nut job, shrieking and chasing Dr. Nora around the station. Roz cries out in glee “Oh Frasier! Your way WAS better!”
Dick Van Dyke Laura tells Rob an artist had done a nude portrait of her, that’s now hanging in a museum. Rob is calm and reassuring. After Laura leaves the room, Rob realizes he’s had his hands on the hot stove burners throughout the conversation.
Star Trek TOS Kirk opens a hatch and gets buried in Tribbles.
LA Law Nebbish lawyer Stuart discovers The Venus Butterfly.
Monk Monk has apparently been run over while in Mexico. The Mexican police captain tells Sharona that Monk showed great courage by crawling through mud and garbage even while dying.
Sharona: - He crawled through what?
Police Captain: - Mud and garbage.
- He’s not dead.
- Pardon me?
- It’s not him!
- Senorita, your friend is gone.
- Maybe it’s the guy that stole our
suitcases? - How can you be sure?
- Adrian Monk would die before he’d crawl
through mud and garbage. - But he was dying.
- You don’t understand.
WKRP Venus gets a tough kid to stay in school by explaining the atom to him in 60 seconds.
The Cosby Show Theo wants to move out, and Cliff uses play money to show him how to budget. After all the expenses are paid, Theo has one bill left. Cliff asks, “Will you have a girlfriend?”
“Naturally.”
Cliff takes the last bill.
Hey, we were both wrong! I just found the clip on Youtube - it’s a guinea pig.
I stand corrected.
It’s still one helluvva jawdropper to hear someone say on broadcast TV, though.
Now, I can’t boil it down to ONE scene- but I have four from TP-
The Dancing Dwarf Dream all the way through to Dale getting on the phone (with bed-hair) to say “I know who killed Laura Palmer!”
Unwrapping the plastic from around Laura’s blue dead face
Leland throwing himself on the casket (and Shelley’s later re-enactment of it using a napkin dispenser)
Dale digging for a agonizingly-long time under Laura’s fingernail for the newsprint
I thought it was a guinea pig!
Also from V- the baby is born!
Also, I always liked the newscast segments at the beginning of the weekly series.
Told’ja so!
(Yes, I’m being funny.)
One show that hasn’t been mentioned. Picket Fences.
Two great scenes - the first when the judge loses his temper, saying he’d retired to this town for a quiet life and keeps ending up dealing with all these weird cases, and …
Where the Sheriff watches the cow give birth to a human baby
Freaks and Geeks: When Bill is drinking beer out of one of those plastic baseball helmets and watching Dallas.
Firefly:
Mal: Now you only gotta scare him.
Jayne: Pain is scary…
Clone High:
JFK: (Telling Abe and Gandhi that they can’t come to his house party)
I will see you there. And by will, I mean won’t!
Because you’re not invited. I, er, wasn’t sure if I was clear on that earlier. So you’re not. Invited, that is.
To my party!
I forgot to wash my hands.