"Baldrick, go forth into the street and let it be known that Lord Blackadder wishes to sell his house!
Percy, just go forth into the street."
Simple, but it cracked me up.
I swear to God, I thought turkeys could fly.
Gee, all the * Get Smart * lately, and not this? When the Chief sends Max on a mission, telling him he will be in mortal danger every step of the way, and Max replies:
“And, LOVING it.”
I have to go with “I’m out!”
hilarious 
Jack Soo as Nick Yamana on Barney Miller, after eating some hash brownies, explains that he likes the way they get ‘mooshy’ when he dips them in his coffee. Throughout the rest of the episode, whenever anyone talks to him, all he’ll say is:
“Mooshy, mooshy.”
The most memorable line from a great series.
IIRC, the line (which certainly qualifies) was “Told you.” (A local radio station is using Cleese’s “the most perfect couple since the beginning of time” in their promos. Always cracks me up.)
Some others I’ve liked:
“Now I know why dogs lick their genitals.” (Red Dwarf. The line following it is totally unnecessary, BTW.)
“Dinsdale.”
“The district attorney is a Republican.” (It’s not funny at all out of context, but it’s the best line in Miracle on 34th Street)
“Daddy’s gonna kill Ralphie.”
“Not craw. CRAW!” (from the first Get Smart episode. Probably considered offensive today, but I think it still works.)
“I have a cunning plan…”
From a recent episode of Friends:
“I do not want my child’s first words to be ‘How you doing?’” (The last three words were uttered in a precious child-like voice.)
Art Carney in * The Honeymooners *
“Hellooooo, Ball”
(he could sell a joke that was probably old even then)
“Hello, Newman”
The barely concealed malice made this that much funnier.
nineiron, I busted out laughing when I read the “feet” line.
I had forgotten about it, but you reminded me how funny it was.
I’d also like to add a couple Seinfeld ones:
No soup for you!
Not that there’s anything wrong with that!
Blackadder again:
Oooh God.
Not a sitcom, but from Young Frankenstein:
Put the candle back.
And from The In-Laws:
Serpentine!
Bruce Campbell
Evil Dead II
“Workshed!”
This brings back a memory of the best delivered, unscripted line:
On ** Mad About You ** Paul is sitting on the couch waiting for Ira to ring the doorbell. His wife Jamie and her best friend Fran are in the other room. Fran’s son Ryan is in a grade school show and Jaime has to go cause Fran is her friend, Paul has to go cause Jamie is going and Ira has to go cause Paul is going.
So Paul is on the couch with Murray the dog, who lifts his leg and starts licking (the dog, not Paul). Paul Reiser the actor’s eyes get huge as he looks around, obviously thinking “What do I do now?” The stage crew and aucidence is going nuts laughing. Finally, the actor Paul thinks up the perfect line, slips back into the character Paul and says:
If I could do what you’re doing, I wouldn’t have to go out tonight.
That kills me too.
I’m also glad to see someone remembers Best of the West. Frog was the ultimate character.
Not technically a sit-com, but whenever I see the clip of the old Carol Burnett show where Tim Conway is describing the siamese elephants (joined at the trunk) he saw at the circus, I nearly pee myself.
Seinfield: Hellooooow!
hhnort!
George Constanza: “George is getting angry!”
-me
For me it is Frank Barone, on the sitcom, “Everybody Loves Raymond.”
“Holy crap!” is his recurring tagline, and the sheer number of ways that Peter Boyle can deliver that line - angry, shocked, or, most often, giddily anticipating an imminent catastrophe - never fails to get me laughing.
- FCF
And don’t forget the follow-up from Joey, who actually liked the meat trifle:
“What’s not to like? Cake…good. Custard…good. Meat…goooood.”