I have a lot, but one of my absolute favorites is:

(from The Cloning)

Meatwad: You asked him to dance! I told you not to ask him to dance!
TV Frylock (to Meatwad): You shut up!
Meatwad: Oh God! Huh...Well. Maybe this is a different show.
TV Frylock: Hey, anybody want some metal candy? (shoots everybody)
Meatwad: It's the same damn show!! Run! Run! Run to your chocolate huts!

Also this:

Carl: Go away. Go away! So tired of this.. Friggin' go away, you freak.
Frylock: Carl, (Carl screams) did you lose somethin' behind the couch?
Carl: Yeah, I did! I lost peace and quiet! What do you need?! What do you want?! Can I not just live here without having to occasionally deal with you animals?!

In Universal Remonster when Frylock puts the TV in the crawl space.
Shake: You will bring that TV back to the house
Frylock says:"No, I won't"
Shake: Then you will help me carry my chair down here
Frylock: No, I won't
Shake: Well then....I will pee all over my pants.

"What does DNA stand for?"-Meatwad
"It stands for Do Not enter my pool...Assman"-Carl

"I only know three words; good, ball, and RAPE"-Hand Banana

"You have seen bras before"-Frylock
"Yeah, but never with the boob meat in them"-Master Shake

"Meat-man... ever since my son was... never born, because I've never had consensual sex without money involved... I've always kind of looked at you as... a thing, that I could live next to... in accordance with state laws." -Carl

A few of my favs...

Meatwad: "Oh... boy, I apologize. My hormones are goin' nuts. Now, please... if you would... get the fuck outta my way. I mean, how many times I gotta fuckin' write "ice cream" on this fuckin' list before someone gets in fuckin' gear, and brings home the fuckin' ice cream? Maybe I should get a steak knife, and etch it in your muthafuckin' forehead! How hard can it fuckin' be? Ice muthafuckin' cream! I guess that's the price I pay for livin' with two fuckin' morons!"

Dr. Weird: Gentlemen!
[a snake is wrapped around his head]
Dr. Weird: Slowly... Carefully... AGITATE THE HELL OUT OF THIS SNAKE!
Steve: Aw, HELL NO!

Frylock: Wow, so you're saying it was fun?
Meatwad: Hell no! That son of a bitch had an axe!

Ignignokt: And everyone under stands how this will come about? Remember, there are no dumb questions.
Moth monster man: Ummm, yeah, right here…
Ignignokt: Yes, the retard with the dumb question?

Meatwad: Okay, uh, I got a two-point question here. One, what's he doin'? Two, should we light him on fire?

Carl: Hey, you grillin'?
Master Shake: No, I'm curing cancer. Of course we're grillin'.
Carl: Are those clouds on fire?

Dr. Weird: "BULLSHIT!!!"

Dr. Weird: "GENTLEMEN!!! I GIVE YOU MORE CORN!!!
Steve: "I don't know, i mean, after last time".
Dr. Weird: "THIS TIME WILL BE DIFFERENT"
Steve: "oh ok..."
Dr. Weird: "ITS NOT DIFFERENT AT ALL NOW IS IT STEVE!!! MUAHAHAHA!!!

Meatwad: "Enchaladitos, they make you wanna eat em!"

meh.. I'll add more later.

Oglethorpe: Whose birthday is it? Someone gets a spanking!

[Meatwad suffers mood swings from being pregnant]
Meatwad: Oh... boy, I apologize. My hormones are goin' nuts. Now, please... if you would... get the f*** outta my way. I mean, how many times I gotta f***in' write "ice cream" on this f***in' list before someone gets in f***in' gear, and brings home the f***in' ice cream? Maybe I should get a steak knife, and etch it in your muthaf***in' forehead! How hard can it f***in' be? Ice muthaf***in' cream! I guess that's the price I pay for livin' with two f***in' morons!

Glass-Bottom Boat Captain: Hi. This is your captain speaking. Welcome to the glass-bottom boat ride at the world famous Trenton Tar Pits. I just want to let you know I'm a convicted sex offender.
Glass-Bottom Boat Captain: Oh-no, ladies and gentlemen, now we're being attacked. Look to your left over the Tarboard side. Giant microscopic Tar Monsters.
Frylock: There ain't nothin' over here but tar and a condom wrapper. This is gross.
[after faking fighting off Tar-Monsters]
Glass-Bottom Boat Captain: OK, I'm back, and we're safe, ladies and gentlemen. They won't be bothering us any more. I chased them off with my nudity.
[pause]
Glass-Bottom Boat Captain: Does that arouse anyone down there?
Meatwad: What does that mean?
Frylock: It means we're gonna get off this boat right now.
Meatwad: Hey, how do I know if I'm aroused?
Glass-Bottom Boat Captain: OK, and we've docked, and I feel a little sexy. Who down there wants to meet the captain and feel sexy with him?

"So i put two and two together there heh, and i decided you're pissin me off" -Carl (bus of the undead)

Ogelthorp: EMORY the Melons are on fire!


Ogelthorp: I have an excellent plan to betra our new friend


Ogelthorp: now what is with all this iterrogation... why dont we just play some frisbee... OVER THERE! WHERE WE WILL MELT YOU INTO FLUID!

Willie Nelson: "I've been known to do a number on lots of cats."
Shake: "Do a number? yeah I bet you'd do a number... in your tights on broadway!"

Shake:"You are the gayest monster since gay came to gay town!"

Shake about carl's new body made of eyeballs:"If I woke up looking like that I would just run to the nearest living thing and kill it..."

Carl:"So they found my car hanging from a tressel under the overpass. They said the guy driving it had a cup-shaped body and a straw-like protrusion. You know anyone like that fry man?"
Frylock:"Oh no Carl, it couldn't have been shake, he was abducted by aliens days ago."
Carl:"Oh yeah, I knew that...I hate you..."