Willy: I warned ya! Didn’t I warn ya? That colored chalk was forged by Lucifer himself!
Operator: The fingers you have used to dial are too fat. To obtain a special dialing wand, please mash the keypad with your palm, now.
Flanders: I think we just hit something!
Homer: I hope it was Flanders!
Burns: Thank you for not making fun of my genitalia.
Marge: I thought I did.
homer: “just because i dont care doesnt mean i dont understand.”
genius. ive used that in conversations so many times.
“Press the police code for the crime being committed. You have chosen Regicide. If you know the name of the King or Queen being murdered, press one or stay on the line…”
linguo: sentance fragment.
Some of these choices are funny (perhaps even witty), but I wouldn’t call them the “Smartest” jokes.
There are some pretty SMART ones from the Bart’s Comet episode:
Skinner: Curse the man who invented helium! Curse Pierre-Jules-Cesar Janssen
Bart: And you’ve never found anything?
Skinner: Once. But by the time I got to the phone, my discovery had already been reported by Principal Kahoutek. I got back at him, though… him and that little boy of his…
Along the lines of Lisa’s perpetual motion invention (I don’t think this particular line has been quoted yet:
Homer: “And this perpetual motion thing is a joke! It just keeps going faster and faster!”
I loved that. 
What would make the joke ‘smrter’, I mean ‘smarter’, is if he had just said, “Curse you Pierre-Jules-Cesar Janssen.”
“Sentence fragment” is also a sentence fragment.
I always liked the episode where Maggie is put in the Ayn Rand Daycare - in one scene on the wall border where you’d expect the alphabet to be posted, it reads instead ‘A is A’.
QUOTE BY MEYER
This isn’t a line as such, but in the episode where Marge takes a painting class (and later paints Mr.Burns) she enters an art contest. Her portrait of Homer (The Bald Adonis) is up against another painting: One of a unicorn on a cliff overlooking a burned, littered, clearcut landscape. There is a thought bubble above the unicorns head that says “Why?”.
Maybe it’s just my art school background, but that send up of bad ‘meaningful’ amature art is priceless. Makes me giggle whenever I think about it.
Totally agree i always love that shot although my brother doesn’t seem to think its as funny, but i know what you mean about the ‘meaningful art’ thing, classic stuff.
Well, if we’re only looking for smart lines:
Homer: I am so smart! I am so smart! S-M-R-T! I mean S-M-A-R-T! I am so smart!
[Linguo’s eyes move back and forth as it thinks]
Linguo: Must conserve battery powrt.
[Linguo shuts itself down]
Here is a bonus-- the full Linguo versus the Mob scene:
First mobster: Hey! They’s throwin’ robots!
Linguo: They are throwing robots.
Second mobster: It’s disrespecting us. Shut up a’you face!
Linguo: Shut up your face.
Second mobster: Whatsa’ matta you?
First mobster: You ain’t so big.
Second mobster: Me an’ him are gonna’ whack you in the labonza!
Linguo: Mmmm… aah… bad grammar overload! Error! Error!
[Linguo explodes]
Hee hee that’s my startup sound…
Bart’s Indian-casino vision quest: Homer, Marge and Bart are having dinner in the White House dining room. President Lisa walks in, followed by a marching band of Marines playing “Hail to the Chief.”
Lisa: Hi, everybody! Sorry I’m late! I’ve been trying to think of nonessential things to cut from the budget.
Marines look startled, about-face, stroll out with exaggerated casualness, eyes to the ceiling, whistling “Hail to the Chief.”
Heck, if it’s SMART you want, you can’t beat Professor Frink:
At “Itchy & Scratchy Land” :
Frink: You’ve got to listen to me! Elementary chaos theory tells us that all robots will eventually turn against their masters and run amok in an orgy of blood and the kicking and the biting with the metal teeth and the hurting and shoving.
Scientist: How much time do we have, professor?
Frink: Well, according to my calculations, the robots won’t go berserk for at least 24 hours.
(The robots go berserk.)
Frink: Oh, I forgot to, er, carry the one.
–
As a substitute teacher at the elementary school, demonstrating a “corn popper” toy for the kindergarden students:
Frink: Mwa-hey, bwa-hai. The compression and expansion of the longitudinal waves cause the erratic oscillation, you can see it there, of the neighbouring particles.
(A little girl attracts Professor Frink’s attention.)
Frink: Yes, what is it, what, what is it?
Little Girl: Can I play with it?
Frink: No, you can’t play with it, you won’t enjoy it on as many levels as I do… Mm-hai bw-ha whoa-hoa. The colours, children! Mwa-ha-lee.
–
After Homer disappears into the wall:
Lisa: Well, where’s my Dad?
Frink: Well, it should be obvious to even the most dim-witted individual who holds an advanced degree in hyperbolic topology, ng-bwui, that Homer Simpson has stumbled into…
(The lights go off.)
Frink: …the third dimension.
(Lisa turns the lights back on.)
Lisa: Sorry.
Frink: (drawing on blackboard) Here is an ordinary square…
Wiggum: Whoa, whoa. Slow down, egghead!
Frink: …but suppose we extend the square beyond the two dimensions of our universe along the hypothetical Z axis, there.
(Frink draws a wireframe cube on the blackboard.)
Everyone: (Gasps).
Frink: This forms a three-dimensional object known as a “cube”, or a “Frinkahedron” in honor of its discoverer, ngu-hey, ng-hey.
–
On the future of computers, as it stood in 1970 or so:
Frink: I predict that within 100 years, computers will be twice as powerful, 10,000 times larger, and so expensive that only the five richest kings of Europe will own them.
–
At his yard sale:
Frink: Good morning, ma’am, good afternoon sir. It passed noon while I was speaking so that was technically accurate.
–
Homer asks the Professor for advice on inventing:
Frink: …and these (handing books to Homer) should give you the grounding you’ll need in thermodynamics, hypermathematics and of course microcalifragalistics.
Homer: Er, look, I just want to know how to invent things.
Frink: All you have to do is think of things which people need but which don’t exist yet.
Homer: You mean like an electric blanket-mobile?
Frink: Www… oh well, possibly. Or you could take something that already exists and find a new use for it, like…
Homer: Hamburger earmuffs.
Frink: Mmm, well, I suppose that would qualify.
Homer: Thanks sucker. (Homer throws the books and runs off)
Frink: Weh, uh, alright, just stay calm, Frinky. (examines his own pair of hamburger earmuffs) These babies will be in the stores while he’s still grappling with the pickle matrix bhay-gn-flay-vn.
–
On the banks of Loch Ness:
Frink: Mmm-hai-hey, let’s see now, we have the Monsterometer, Flipper-finder, Hoax-a-scope which is important for the looking and finding…
–
With his fellow MENSA members:
Frink: Zounds, someone took our gazebo!
Another Frink/Homer exchange:
Frink: I take it from that little impressed noise that you are interested in purchasing that matter transporter, sir.
Homer: (not fond of the price, hearable in voice) Ummmmmmm… two bucks… it only transports matter… ummm… well, ah… I’ll give you thirty-five cents.
Frink: Sold! But I must warn you, this device carries a frighteningly high risk of catastrophic–
Homer: (annoyed) I said I’ll take it!
Saw a new one last night that might qualify
Lisa and Skinner at a posh preparatory school
Lisa: “Their periodic table has 250 elements.”
Skinner: “Our school boards cut us back to sixteen — all of them lanthanides.”
Sometimes, the most clever things are what are on various signs around town:
“Springfield Baptist Church - We put the ‘fun’ back into ‘fundamentalism’” (this is a running gag - I’ve also seen “Springfield Mortuary - we put the ‘fun’ back into ‘funeral’”, and several others I can’t recall)
Also, the ‘Dancing Homer’ episode where they go to the game in Capital City and go past the concession stand and see the ‘Dancing Homer’ t-shirts
Marge: “Who would have imagined a Simpson on a t-shirt?”