From the same episode, TWO quotes that I can’t believe they let on the air:
“That’s the last time you’ll slap your Willie around.”
“Now, Nibbles, chew through my ball sack.”
Kent Brockman: “Ladies and gentlemen, er, we’ve just lost the picture, but, uh, what we’ve seen speaks for itself. The Corvair spacecraft has been taken over — ‘conquered’, if you will — by a master race of giant space ants. It’s difficult to tell from this vantage point whether they will consume the captive earth men or merely enslave them. One thing is for certain, there is no stopping them; the ants will soon be here. And I, for one, welcome our new insect overlords. I’d like to remind them that as a trusted TV personality, I can be helpful in rounding up others to…toil in their underground sugar caves.”
JANITOR WILLIE [dressed in a kilt, addressing the school crowd at “Scotchtoberfest”]: When we went inta battle, we dinna wear kilts! We wore full-length ball gowns! The sequins dazzled the enemy!
[balloons Bart has surreptitiously attached to the kilt rise, indecently exposing Willie]
PRINCIPAL SKINNER: Well, Bart, I see you fell for our little sting operation! You see, there’s no such thing as Scotchtoberfest, and you just earned yourself three weeks in detention!
WILLIE: No such thing as Scotchtoberfest?! [sob] Ya used me, Skinner! Ya used me!
[during investigation of Mr. Burns’ shooting]
WILLIE: I tell ya, I kinna fire a gun! Look at me thumbs! [shows permanently crooked thumbs] I got it from Space Invaders back in the '70s!
CHIEF WIGGUM: Yeah . . . That was a pretty addictive game!
WILLIE: Game?!
“There’s very little meat in these gym mats!”
“Call me back, Ishmael.”
I know that’s come up before. Explain it to me, please?
A favorite sight gag: Chief Wiggum comes into work and sees the answering machine for the 911 line, with several dozen emergency messages on it. He hits a button and it resets to zero.
“Sneed’s Feed and Seed” rhymes. What would rhyming require if the first word were “Chuck’s”?
Old joke (from the '60s or earlier):
FIRST DAUGHTER: Mother, I’m going out with Pete to eat!
MOTHER: All right, dear!
SECOND DAUGHTER: Mother, I’m going out with Vance to dance!
MOTHER: All right, dear! Be home early!
THIRD DAUGHTER: Mother, I’m going out with Chuck!
MOTHER: Oh, no, you’re not! You’re staying right here!
Homer: Aw, twenty dollars… I wanted a peanut.
Homer’s Brain: Twenty dollars can buy many peanuts!
Homer: Explain how!
Homer’s Brain: Money can be exchanged for goods and services.
Homer: Woo-hoo!
Homer (looking up at the ceiling): Oh, Lord, why do you mock me?
Marge : Homer, that’s not God, that’s a waffle that Bart threw up there.
Homer: I know I shouldn’t eat thee… [eats waffle] Mmmm…Sacrelicious.
Homer’s brain: Don’t say “watching porn.” Don’t say “watching porn.”
Homer: Watching porn.
Homer’s brain: D’oh!
HOMER [about to take a night-school science class test, so he can ratify his high-school graduation and win back his Most Improved Body Odor award]: All right, Brain! You don’t like me, and I don’t like you! So just get me through this, and I’ll get back to killing you with beer!
HOMER’S BRAIN: It’s a deal!
I forget the context exactly, but Homer needed an alibi…
Marge: Where were you last night?
Homer’s Brain: Uh oh, can’t let Marge know where I was…
Homer: Pornography. I was buying pornography.
Homer’s Brain: Heh heh…I would’ve never thought of that.
I don’t like you and you don’t like me.
I like you.
Well I don’t like you.
Maybe if you get to know me you might.
I forgot who said what.
He then says, “Why can’t the people in this town take the law into their own hands?”
The episode in question was what I think of as the Gabbo episode, although others may call it the Krusty’s Komeback Special episode.
Gabbo had snaked Itchy and Scratchy out from under Krusty’s nose, and all that remained for him to show was the Eastern European (Cold War Era) Worker and Parasite, IIRC. My favorite part was when the 'toon was over and tha camera cut back to Krusty. He’s standing there wth his mouth hanging open, an unlit cigarette dangling from his lower lip. A Zippo lighter is aflame about an inch away from the tip of the cigarette.
Krusty: What the hell was that?
Insurance Adjuster: Our records show that last night you made purchases at a place called “Moe’s”. What sort of place is that?
Homer (thinking: I can’t let him know I was at a bar before I crashed my car. I’ve got to think of something, fast!
Homer: Moe’s is a pornography store. I was buying pornography.
Mention of the one-time screening of the Cold War Soviet Bloc cartoon Worker and Parasite on Krusty’s show called to mind another Simpsons jab at the defunct era: when Homer is looking to buy a used car at “Crazy Vaclav’s” and is shown a car (that resembles a Yugo hatchback… Remember the Yugo?) with Cyrillic letters on the gear shift. “What country was this made in?” asks Homer, and Vaclav admits, “It… It no longer exists.”
He then exhorts Homer to “Put it in H!” when the car stalls, “H” being the Cyrllic letter for the “N” sound, indicating Neutral 
My favorite Homer excuses to Marge (which I sometimes try out on my own wife):
“Marge, it takes two to lie: one to lie, and one to listen!”
Or in response to a direct yes/no query: “Marge, I won’t lie to you.” (Silence)
“But Marge! I was a political prisoner! … I kicked a giant mouse in the butt, do I have to draw you a diagram?”
Or when Marge tells him to just appreciate that his “Flaming Homer” concoction, being sold by Moe as “Flaming Moes”, is making people happy: “Oh look at me! I’m making people happy! I’m the magical man, from Happy Land! In a gumdrop house, on Lollipop Lane! (slams door, then reopens it) By the way, I was being sarcastic.”
In the same vein: “Marge, you’re my wife and I love you very much, but you’re living in a world of make-believe. With flowers and bells and leprechauns, and magic frogs with funny little hats.”
“Oh honey, I didn’t get drunk. I just went to a strange fantasy world.”
“A woman is a lot like a beer. They look good, they smell good, you’d step over your own mother just to get one… But you can’t stop at one, you wanna drink another woman!”
Or as Homer so famously declared, “To alcohol - the cause of, and solution to, all of life’s problems.”
Once he described his favorite recent movie. “It was about a bus that had to speed because if it didn’t speed it would blow up. It had to maintain a constant speed or everyone would die, so the driver had to speed the entire time. Man, that bus could really speed. I think the movie was called The Bus That Couldn’t Slow Down.”
During negotiations over nuclear plant workers’ contract, we learn that Homer’s union is the International Brotherhood of Jazz Dancers, Pastry Chefs and Nuclear Technicians, Local 643. (To think that there are at least 642 other locals!) And the union logo shows the outline of a dancer, over a cupcake, over an atom. 
Thought of this one this morning, after the husband used it and I realize we use it quite frequently whenever something is a bit unclear:
Jasper: “Who shot who in the what, now?”