In A Scanner Darkly, Robert Downey plays an annoying know-it-all with paranoid delusions. He keeps going to the police with his latest rambling accusations about Keanu Reeves’s character, and by the end of the movie the detectives throw him out of their office. As a cop is escorting him out, Downey asks, “If I’m to be incarcerated, shouldn’t you be issuing me protective lotions?”
Every time I think about that line, I still giggle.
Your tickle line?
I still remember this old western playing in the background while I was studying for a college math test. I wasn’t watching the screen at the time when the one character told the other “strap this on and be a man”.
I think it was a gun belt, but still hilarious at the time!
Mine’s from The Magnificent Seven. In response to being asked “You elected?” after a shootout, Brynner (IIRC) says, “Nah. Got nominated real good, though.”
“As God is my witness, I thought turkeys could fly!”
Star Wars. During the battle over the Death Star, when Wedge (one of Luke’s fellow X-wing pilots) gets shot up, Luke says:
“Pull out, Wedge! You can’t do any more good back there!”
Ohh, how the mind wanders… 
“Where your white women at??” - Blazing Saddles
“My food is problematic.” - Firefly
Billy Connolly on a talk show:
“That’s about as welcome as a fart in a spacesuit!”
I just watched The Mummy 3: Dragon Emporer Tomb Raider of the Lost Something.
The funniest line in the entire line was John Hanna with a machine gun blazing out of an open airplane door screaming, " Die You Mummy Bastards DIE!"
Black Adder III:
“My consumption grows evermore acute and Coleridge’s drugs are wearing off.”
Really, most of the Black Adder one-liners…
From Clue: “…ran down the hall…”
While You Were Sleeping, from a very exasperated Sandra Bullock:
I’ve had a rotten Christmas, you’ve just managed to kill my New Year’s. If you come back on Easter, you can burn down my apartment.
From an otherwise very forgettable post-nuclear-war sitcom called “Whoops!”:
“The Volvo proved even safer than advertised.”
Just about every line in Quest for the Holy Grail but this is an off the beat one that I think most people missed… In Father’s Day with Billy Crystal and Robin Williams who play two possible dads to child of same college sweetheart, played by Nastasha Kinski, who comes to both of them seperately to ask for help in finding the runaway kid. They encounter each other on the trail of the boy and search together and at one point Crystal urges Williams to cry in order to win sympathy. Williams protests that he can’t just cry on command. Crystal tells him to think of something sad, “like Lou Gehrig”. Williams asks, “who’s Lou Gherig?” Incredulous, Crystal explains about the great ball player ending with, “He died of Lou Gherig’s disease”. Williams deadpans, “Whoa, what are the odds?”
I fell out of my seat and could not stop laughing every time I thought about it for the rest of the movie, much to my mother’s dismay and humiliation. Just cracked me up.
And I’m often known to wail, “Help, help, I’m being repressed!” and “Come see the violence inherent in the system”.
Kramer: I’m Out!
“Real tomato ketchup, Eddie?”
“Chicken pot, chicken pot, chicken pot piiiiieeee.” - Donny in Just Shoot Me.
If you haven’t seen it, I can’t explain it other than to say that in an otherwise mediocre show, this particular episode was some kind of comedic tour de force. It just slays me every time I hear it.
Also, Jim Gaffigan’s “Hot Pockets” from his stand-up routine. Hmmm, I seem to sense a general theme here.
Crockett and Tubbs! They’re floatin’!