Mayor Quimby, upon being informed that an election is coming up.
Not random pedestrians; he was keeping looters at bay during the hurricane episode.
Chief Wiggum, after telling Ralph, “Son, whether you wanna win a girl or crack a nut, the key is patience.” He then finds a nut that won’t crack immediately, smashes it with the butt of his gun, and when it still won’t crack, shoots it.
Fat Homer ordering a movie ticket to see the Oscar-winning Honk If You’re Horny.
A few more…
“Ooooooooooo! Floor pie!”
“You know how I feel about fake kidnappings.”
“Mmmm. Sacrilicious…”
“It’s sheer flattery. But I’ll allow it.”
“Motivated seller!” (Bonus points if you know the entire conversation of which this is a part)
“How vonderful!”
Homer, in the Junior Camper’s episode.
Homer again, in the Flanders & Homer BFF episode, while eating “That’s not God! That’s just a waffle Bart tossed up there!” “I know I shouldn’t eat thee, but…”
Lionel Hutz teaching Marge how to put a positive spin on crappy houses in the episode where she becomes a realtor. The house in question still had chalk outlines from corpses on the living room floor, if memory serves (it wasn’t the “murder house,” though).
Just for the heck of it, here’s a special Godwin’s Law edition:
“I’m surrounded by Commie-Nazis!”
“They won’t save your brain, Hitler!”
“No, but can I interest you in some authentic Nazi underpants?”
“Ach du lieben! Das est not ein boobie!”
“We’ll be rich, rich as Nazis!”
“Outta my way! I’m Hitler!”
That was the episode where Grandpa describes what he did during the war: he crashlanded in Germany (?) and waited out the war dressed as a female cabaret star in Berlin.
The first quote is by C. Montgomery Burns, although I cannot remember the exact context at the moment. (I am so ashamed.) 
The second is by Bart when he jumps in Hitler’s car at the state fair and it rolls off its perch.
“Marge, they’re just hams”
I think that was the one-armed gun store salesman, after failing to talk someone into buying something. (Vague! Yay!)
Homer to Marge after Santa’s Little Helper joins the family again after being a Duff Spokesdog. She commented she is out of celebration ham, and only has other types of hams.
“Ho-mer Simp-son!”
“I’m surrounded by Commie-Nazis!”
Rainer Wolfcastle in a movie trailer where he has to deliver the UNICEF pennies out of a burning cargo plane.
“They won’t save your brain, Hitler!”
I believe it’s an Abe flashback, when he is a sniper about to kill Hitler, and is knocked off his mark by Private Burns’ tennis ball.
(Finally, I get to answer some, having come into the thread late!)
That would be the Fighting Hellfish episode.
ZJ
Not exactly. The house in question was actually on fire.
Damn! And that is one of my favorite episodes ever.