I just finished watching the fourth-season episode “A Streetcar Named Marge.” It was hilarious on so many different levels. I laughed out loud at the Ayn Rand School for Tots and the brilliant parody of The Great Escape.
A lot to choose from, but one of the best would have to be Homer referring to Stephen Hawking, in his motorised chair, berating the Springfield Mensa group, as Larry Flynt.
I always loved how Linda Ronstadt randomly showed up in Barney’s Plow King ad in the “Mr. Plow” episode. And how his nonchalant response when asked how he got her to appear in his ad just raises more questions than answers, namely how does Barney know Linda Ronstadt?
I was a late adaptor to the Simpsons, not really paying any attention until out of the corner of my eye I caught Homer slamming into a deer statue with his car, and crying out “D’oh!” Lisa yelled “A deer!” and Marge chimed in with “A female deer!”. Somehow that tickled me so strongly I became a fan. That was in season 5, “Bart gets an elephant”.
I used to watch the show all the time with my daughter when she was little (20-odd years ago). We both laughed out loud at how Homer pictured his wife in “Marge on the Lam”:
The sign on the feed store in the “Tomacco” episode: “Sneed’s Feed and Seed (Formerly Chuck’s)”. Maybe the naughtiest TV joke snuck past the censors ever.
Mine are mostly Homerisms:
“Ahh, the Luftwaffe, the Washington Generals of The History Channel.”
Two of the best parodies ever:. The second one is so '80s!
And I can never forget their “Game of Thrones” opening either.
An early favorite:
Also:
I think at least 8 of the top ten Simpsons episodes would probably be Treehouse of Terror installments.
“As always, silence means ‘Yes’…” 
My favorite Simpsons song: “See My Vest”
Was about to post that.
Apu had some of the best lines. “Oh, My Goodness! What has been implied here???” and “Get Out of my Store and Please Come Again!”
Of course, I routinely quote, “Release The Hounds!”
When I think about it, a few of my favorite moments are from songs.
“I am Iron Man, duda duda duda do vote for me.”
“From the day your are born in the alley, to the day you are hit by a car.”
“I hate every ape I see, from chimpan-a to chimpan-z.”
Other favorites:
Is this the end of zombie Shakespeare?
I am familiar with the works of Pablo Neruda.
And possibly my favorite of all:
My all-time favorite Simpsons moment involves Homer buying a gun.
Gun shop owner: “Sorry, the law requires a five-day waiting period. We’ve got to run a background check.”
Homer: “Five days? But I’m mad NOW!”
“Marge, an eagle is our country’s mascot. Fighting him would be like kicking George Washington in his wooden nuts!”
“Arnie, this is not the time.”
“You’re not the time, Kent! You’re not the time!”
“But all is not well in jockey town…”
Sung to the theme from Laurence of Arabia: “I am so thirsty…”
The whole sequence in which Marge ambushes the Nazis in a movie theater.
Dr. Hibbert: “Old man river…”