"He spelled 'Yale' with a 6." "I'm not made of Airports"

Lisa, watching TV with Bart: Do you suppose that sceptre is metal or plastic?
<Bright flash of light from TV, followed by thunder>
Bart: It’s metal.

Lisa, exhausted from lack of sleep: “Am I using too much glue?”
Cow on the glue bottle: “You won’t eat our meat but you’ll glue with our feet!”
Lisa: “AAHHHH!”

BURNS: How would you like it if I was humping you leg and slobbering all over your crotch?

SMITHERS: If you did it Sir?

Smithers: “Ah… You should probably ignore that.”

(From when Lisa visits Smithers’ house for help in finding the “real” Malibu Stacy, his computer login screen is seen to be a digitally animated photo of a naked Mr. Burns, saying: “Hello… Smithers. You are quite good… at… turning me on.”)

And when the Germans take over the plant and interview Homer, just before he spirals off into “The Land of Chocolate”:

German: You have been safety inspector here for two years. What initiatives have you spearheaded in that time?
Homer: Uh… All of them?
German: I… see.

Hans Moleman: “Alcohol has ruined my life. Look at me! I’m thirty-one years old!

Random quotes, you’ll know who said them and when and how if you’re a fan:

“If only we had listened to that boy… Instead of walling him up in the abandoned coke oven.”

“He’s going to smell like hot dogs!”

“Oh my God! He’s like some kind of… non-giving up… school… guy!”

“Roger Meyers Sr., the gentle genius behind Itchy and Scratchy, loved and cared about almost all the peoples of the world. And he in turn, was beloved by the world… Except in 1938, when he was criticized for his controversial cartoon Nazi Supermen Are Our Superiors.”

“Marge Simpson: we have also arrested your older, balder, fatter son.”

…“But Marge! I was a political prisoner!”
“HOW were you a political prisoner?”
“I kicked a giant mouse in the butt! Do I have to draw you a diagram?!”

“This is not as hot a party as I had anticipated.”

“Uh, you’ve got the wrong number. This is 9-1… 2.”

“Some days, we don’t let the line move at all. We call those days weekdays. Heh-heh… Heh.”

HOMER: Bees are on the what, now?

And how could nobody have mentioned what’s become some widely repeated memes:

“Arrgh! My eyes! … The goggles do nothing!”
(often mis-repeated as “The goggles, they do nothing!”)

Embiggens? I never heard that word until I moved to Springfield.”
“It’s a perfectly cromulent word.”

And more now that I’m typing again:

Skinner: It was a trap! There’s no such thing as Scotchtoberfest!
Willie: Nae such thing —? Ye uuuuused me, Skinner! Ye uuuused me!!

Why, oh why did I register with Insta-Trace?

A partial quote was given earlier, but the full quote is much, much funnier:

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.

Mr. Burns: [Taking Marge on an expedition] What do you think, Smithers?
Smithers: I think women and sea-men don’t mix.
Mr. Burns: We know what you think.

In this house, we obey the laws of thermodynamics!

This comic is appropriate to the subject at hand.

Bart falls out of a tree.

Nelson: Ha, HA!
Milhouse: Hey Nelson, he’s really hurt, I think he broke his leg!
Nelson: I said “Ha, Ha!”

Homer, in the space shuttle, floats dangerously close to the glassed-in ant farm…

Ant1: “Danger! Danger! Protect the queen!”
Ant2: “Which one is the queen?”
Ant1: “I’M the queen!”
Ant2: “No you’re not!”

Homer crashes into the glass, spilling the ants everywhere.

Ant: “Freedom! Horrible, horrible freedom!”

Buzz Aldrin: “You fool! Now we may never know if ants can be taught to turn tiny screws in space.”

And Homer, after being assaulted by the Krusty doll runs naked & screaming through the kitchen…

Patty: “There goes the last shred of my heterosexuality.”

And after Bart has suckered the entire church congregation into singing “Ina-Gadda-Da-Vida”…

Rev. Lovejoy: Wait a minute. This sounds suspiciously like rock and/or roll…"

“Big deal! When I was a boy, we used to get spanked by Presidents ALL the time! Grover Cleveland spanked me on two non-consecutive occasions!”

TV shows image of Homer, accused of “kidnapping” Larry Burns, trying to break through a police line and falling in a hail of gunfire.
Simpson family: AAAH!
Kent Brockman: A bloody end for Homer Simpson. …Is just one of several possible outcomes, according to our computer simulation! Now, here’s how it would look if the police killed him with a barrage of baseballs.

“They’ll never know the simple joy of a monkey knife fight.”
“Circle, circle, circle… Now stab! Stab stab stab! Ho-ho, he ain’t pretty no more!”

Lisa: Didn’t you wonder why you were getting checks for doing absolutely nothing?
Grandpa: I figured it was because the Democrats were back in power.

Satan summons Richard M. Nixon, as yet alive when originally aired, to be on his Jury of the Damned.
Nixon: But I’m not dead yet! In fact, I just wrote an article for Redbook.
Satan: Listen, I did a favor for you – !
Nixon bows his head: Yes, Master.

(At the meeting of Springfield Republicans):
Mr. Burns: And now, Bob Dole will read from The Necronomicon.
Bob Dole (in hooded cloak): Ezak iziri golanus. Maledictu nosferatu in principi…

Can’t sleep. Clown will eat me.

Still? Nobody?

Flanders (at the orchard): How long have you been here?
Homer: Twenty of the suckiest minutes of my life.
Ned: Ho ho ho, suckin’ down the cider, huh?

" Look at the dog with the fluffy white tail!"

Agnes Skinner: “Who are you, the possible police?”

See top of page 4.

My guess is the Halloween episode where Dr. Hibbert, a la Dr. Moreau, has an island where he’s morphed all the citizens of Springfield into “manimals”.