From "Lucy Does a TV Commercial", Lucy pretends to be on TV... inside their TV. Here are some of the highlights.
Ricky's first look at Lucy on TV: "You know, I can't get over how clear the picture is."
When Lucy accidentally dropped something and she had to pick it up: "Well, what you know? Third-dimensional television."
Fred's clapping is pretty good.
And of course, "For our first offering this evening, we- STOP THAT NOW! Go back and sit down!"
Then there's the episode's timeless second act, Vitameatavegamin — The single funniest sketch in the history of television. So funny even the other actors can't contain their laughter.
Possibly one of the single funniest moments on live-action television was from the very end of the show's run. They moved to a farm during this series. This particular episode they decided to try to raise chickens. The chickens weren't maturing fast enough to suit Ricky, so Lucy and Ethel began buying eggs to plant into the chicken's nests. When Ricky came home early they hid the eggs by stuffing them into Lucy's blouse and Ethel's back pockets. Ricky then insisted Lucy practice a tango routine with him that the two of them needed to do later that week. The end result was an egg-soaked Lucy and a live audience that laughed for over a minute and a half. It was considered a record holder for years, and may still be one. As a cherry on the sundae, Fred opens the door into Ethel's backside, crushing all the eggs in her back pockets.
King Kat Walsh's response to seeing Fred in a raccoon coat: "Dig that crazy dancing bear!"
From "The Moustache":
Ethel: My grandfather used to have a moustache — a great, big, long handlebar one — and Grandma got rid of it in the middle of the night.
Ethel: She tied it around the bedpost when he was asleep and then yelled "Fire."
Lucy: Stuck in the door at 310 East 69th Street. I was kicked down stairs, bitten by a dog, and chased three blocks by a policeman who wanted to see my peddler's license. One more hour, they'd have reported the death of another salesman.
Superman: You mean to tell me that you've been married to her for fifteen years? Ricky: Yes, fifteen years! Superman: And they call me Superman.
Lucy and Ricky's shocked faces are the cherry on top of that sundae.
Lucy inadvertently splicing a skit she and the Mertzes did, along with Ricky's home movies, into Ricky's audition reel for a gig. She basically performed YouTube Poop 50 years before YouTube.
"Lucy is Envious"; specifically, the scene where Ricky and Fred (disguised as Martians) scare the bejeezus out of Lucy and Ethel. Once the Martians leave, Ethel shouts, "Call the police!" Lucy screams in response.
The whole sequence where they pretend to be Martians and the ending was pretty funny too.
The episode where they open a diner. Ricky and Lucy end up talking to and greeting the customers, while Fred and Ethel end up slaving away in the kitchen. After a feud, the couples agree to split the diner IN HALF. Cue the sequence where a customer comes in and asks for a hamburger. The couples try to get him to buy from THEM a hamburger and Fred and Ethel end up going down to a one cent hamburger. Lucy then calls the customer over to her side, whispers something in his ear, gives him a dollar from the cash register, and the guy goes over to Fred and Ethel and asks "I'd like 100 hamburgers." And Fred and Ethel's response: "I'm sorry we're all out of hamburgers."
The pie fight at the end. Especially where the said customer throws a pie in the face of the former owner of the diner after he hears that he cheated Lucy, Ricky, Ethel, and Fred out of their money.