From Circle, a highly underrated little caper movie:
Eddie Izzard playing Troy, who is essentially a loan shark with a tendency to burst into song, in regards to Leo, the “hero” of the piece, who is being chased down the street by a very angry second thug:
“He can’t kill him. I’m gonna kill him.”
It’s my favorite line ever, surpassing ‘I am serious. And don’t call me Shirley.’
Mom’s favorite is actually “Over Macho Grande?” 
Whereas I like “Jimmy … do you like movies about gladiators?”
There was a commercial for Lipton Brisk iced tea. It featured stop motion NY Yankees, including George Steinbrenner, Babe Ruth, and Billy Martin. Ruth is at bat looking hot and uncomfortable and Steinbrenner bellows " Martin, all he’s doing is sweating. I’m not sweating and I’m wearing a turtleneck. You’re fired!"
Now Martin had been dead for several years, but I liked that Lipton had thrown in an old “Steinbrenner is always firing Billy Martin” joke, even though it wasn’t necessary for the commercial.
I get a chuckle out of the ad for the upcoming Serenity flick. During an argument over something or other, there is this exchange:
hunky captain: Do you want to run this ship?
irascible first mate: YES!
hunky captain: (flustered) W-well…you can’t.
(Mind you, I’m not one of those obsessive Joss-Whedon-can-do-no-wrong-and-the-“toad”-line-from-the-X-Men-was-all-Halle’s-fault fanatics. I watched “Firefly” once and wasn’t impressed. I’m not waiting with baited breath for the flick. But that little exchange tickled me.)
Martin?!? What about the poor dead Bambino? I don’t think Lipton was the Babe’s first choice of a thirst quenching drink though. 
My contribution to the thread comes from “Cheers”. Someone mentioned the old question, "If a tree falls in a forest and no one’s there, does it make a sound? and Coach asked, “Well, if no one was there, how do you know it fell? Maybe some beavers set it down there.”
From Raising Arizona:
“Son, you gat a panty on your head.”
“…so this one time in band camp…”
From the ABC Disney Sat morn cartoon RECESS, the fashionista “Ashleys” are forcing tomboy Spinelli to join them- and in homage to the old 1930’s shocker film FREAKS, they chant “One of us…one of us”.
AND LATER IN THE SAME EPISODE- they have Spinelli tied to a chair with her eyelids taped open, forcing her to watch “My Little Pony”.
A TWO-PLAY FOR A DISNEY KIDS CARTOON- REFERENCING FREAKS AND A CLOCKWORK ORANGE!!!
I came in here to mention that. Once I realized it was a Joss Whedon thing, it made perfect sense. But it was very funny.
My two favorite “unexpected” moments didn’t have dialogue.
The first was an ad and I don’t remember for what. Might have been beer. Anyway, the scene was a ship christening. Pretty girl swings bottle against ship and BAM! The whole ship disintegrates!
The second was an episode of the old “Dave Allen At Large” show. English cop walking down the street notices car with windows rolled up. Inside is man in full scuba gear. Cop raps on window with nightstick. Diver rolls down window and out pours gallons of water!
Speaking of Firefly…
One word, from The Train Job, the first episode to air:
“Darn.”
From Family Guy (and I hope I’m remember the quote correctly):
Tom Tucker: “Up next…a pig that won’t eat Jews?”
Many children’s cartoons poke fun at pop culture. But one of the funniest gags that caught me by surprise on a kids show was on a rather unfunny sketch comedy show that airs on Nickelodeon called All That. (It used to be funny back in the day, as I recall, but maybe that’s just young age. I dunno.) A sketch taking place at a birthday party opened with the kids at the party singing (to the tune of For He’s A Jolly Good Fellow) “For it’s a jolly good birthday! This song is public domain!” I wonder how many of the kids watching got that one.
The Young Ones
While Rick lays helpless, face down & spread eagle on the floor, Vivian gives him a vicious smack to the groin with a cricket bat.
Rick: Ha! You missed both my legs!
The frying pan scene in Throw Momma From the Train. “You lied to me!” CLUNK!
I don’t get it.
See, (the undercover) Drebin (at the locksmith’s shop, I believe) answered BOTH questions (“who are you” and “what are you doing here” with the SAME simple response.
That should be, "Who are you, and how did you get in here?"
“Man, I am going to SHOOT you in the FACE!” - Asshole Cop
Reservoir Dogs.
“I feel like theives are breathing down my neck.” - some actress who I can’t remember
(as he breathes down her neck) “Thieves aren’t breathing down your neck.” - Charles Grodin
The Great Muppet Caper