Dr. Nick: Flammable and inflammable mean the same thing? What a country!
Quimby in one of the haloween specials, after he’s insulted the french frog legs or something like that
“I stand by my racial slur, do your worst you filthy pretentious swines”
Sorry, that’s a Homer quote.
[at the ethnic used car dealer]
Homer: What country is this car from, anyway?
Dealer: It no longer exists. But it goes twelve hectares on a single tank of kerosene!
Jacques (the bowling instructor): My mind says stop, but my heart, and my hips, cry proceed. Marge darling, I want to see you tomorrow. Not at Barney’s Bowlorama, away from the thunderous folly of clattering pins. Meet me tomorrow for Brunch.
Marge: What’s Brunch?
Jacques: You’d love it. It’s not quite breakfast, it’s not quite lunch, but it comes with a slice of cantaloupe at the end.
Lisa: Wait! Those aren’t crash test dummies!
Fourth Reich Motors Guy: This exhibit is closed.
Moe - Err we dont like the word ‘mutants’ Homer, we prefer freaks, or monsters.
Flanders - I dont see any reason why us freaks and norms cant get along
Rev Lovejoy: Marge have you ever sat down and read this thing [the bible]? Technically, we’re not even allowed to go to the bathroom.
Two of my favs from Apu:
“Mr. Homer, you may emerge from my chips now. The opportunity to prove yourself a man has passed.”
and of course, the ever popular:
“Ah, the searing kiss of hot lead, how I have missed you. I mean, help, I think I am dying.”
Well, sort-of. Adam was conflating with another Reverend Lovejoy line, from the episode “Bart’s Girlfriend”. Bart has been accused of stealing collection-plate money, but it was actually Jessica Lovejoy, the Reverend’s daughter. Lisa, knowing the truth, addresses the congregation:
Lisa: I know most of you have already judged my brother guilty without any proof, but doesn’t the Bible teach us, “Judge not, lest ye be judged,” Reverend?
Lovejoy: [sullen] I think it may be somewhere towards the back.
There’s one about gambling where Homer tells Lisa the bible says it’s okay. When she asks where, he says it’s somewhere in the back.
Then one about whacking day when Lovejoy reads Lisa a bible quote promoting whacking day. When she asks if she can see it, Lovejoy shuts the bible and say “no.”
My favorite is when Moe is talking to all the bar regulars about the dangers of drunk driving:
“Yeah, all right. Listen up, guys. The Springfield Police have told me that ninety one percent of all traffic accidents are causes by you six guys”
This is an easy one for me. Moe is on a date and is very eager to impress the lady:
Waiter: What can I get for you sir?
Moe: Yea ahhhhh just give me the most expensive thing on the menu stuffed with the second most expensive thing.
Does anybody pick nits like a Simpsons fan correcting quotes? 
Waiter: Very good, sir. Lobster stuffed with tacos.
My fav has always been this two parter:
Ron Howard: Homer, you smell like vodka and glass clippings.
Homer: It’s a drink I made up myself. It’s called a lawnmower. You want one?
Ron: Yeah, OK.
Then later in the episode
Ron: Homer, we’re out of vodka.
Cletus (atop a telephone pole): Hey, I could call my ma from up here…HEY MA!
Apu: Tonight I’m going to party like it’s on sale for $19.99!
Burns: Who the devil are you?
(As Homer stands with a paint can under the giant words ‘I am Homer Simpson’.)
My favorites haven’t been said yet…
Dr. Nick: HI EVELEYBODY!
Ralph Wiggums: My cat’s breath smells like cat food.
Ralph again (and my personal favorite): I bent my Wookie.
Ok here goes…feel free to correct me, these are all from my (faulted) memory:
Krusty: “Burn that seat”
Moe (to Helen Hunt’s character: “Don’t eat for a week, because I’m taking you out for a steak the size of a toilet seat.”
Rod or Todd: “Ow, my freakin’ ears!”
Russian Girl: “After Chernobyl, my penis fall off”
Moe: “And penis is Russian for…?”
Bart: My mom has an earring, does that mean you think my mom’s cool?
Milhouse: I don’t think your mom’s cool…I think she’s HOT!"
This whole thing about Krusty getting canned and being replaced with a infomercial for hemmorhoid remedy. Krusty is willing to play Hemmorhoid Sufferer #1. When he’s turned down, he shouts out, “Wait, I can be one of the ‘after’ guys! ‘Ah, that’s better. I can ride a bike again!’” Very funny.
Mr. Burns: If you can take advantage of a situation in some way, it’s your duty as an American to do it. Why should the race always be to the swift, or the Jumble to the quick-witted? Should they be allowed to win merely because of the gifts God gave them? Well I say, ‘Cheating is the gift man gives himself.
Moe: Yea, Hi, I want to order an escort.
Lady over phone: Okay, sir, where to?
Moe: To where!? How about orgasmville!?
( I butchered it, please correct me)
Sea Captain (on the phone): Call me back, Ishmael.