In the scene at Monk's where Kramer says that no one was at the post office, Jerry says "Today's Sunday." If you read the business hours of Monk's on the red plaque near the cash register you can distinctly make out "Closed Sunday"
Kramer comes into Monk's and notes to Jerry and George that while he was protesting against the post office, not one person went into the building. Jerry then remarks that it's Sunday and the post office is closed. In the next scene, Kramer is walking down the street and Newman, in uniform, drives up next to him in a mail truck. However, if it was supposed to be Sunday, then Newman should have been off of work.
It seems odd that George heard that Kramer got "mugged" on a babysitting gig when Kramer and Elaine were the only people involved and they both knew it wasn't a mugging.
When Elaine baby-sits the second time, Vivian's house is shown from the outside, and it's clearly daytime. Also, when Vivian comes home, you can see through the window that it's light out. Why then is Jimmy asleep in bed?
It seems unlikely that Jerry would have no scrapes, bruises, or other wounds after being dragged behind a car.
When we see the outside of the blood bank early in the episode it is definitely apparent that the bank is located in the city. When Kramer is driving his blood from the apartment building to the bank in Jerry's car we see him driving down a highway that is definitely not in the city. He wouldn't drive from the Upper West Side, out of the city and then back into the city to move the blood.
Kramer mentions to Jerry that he was ambushed by the "neighborhood kids", including Joey Zambino, who Kramer previously babysat in the season 7 episode "The Wait Out".
When George asks Kramer if he wants to go to Queens to fix his fathers screen door Kramer says yes as he's getting a drink out of Jerry's fridge. Then Kramer walks away and in the next shot the fridge is closed without anyone closing it.
George calls Jerry and tells him that Play Now had downgraded him to "some sort of a bunker". However, we later see that his office is on a higher floor.
Goof: George's boss tells George that he saw him carrying the 200 lbs motorized scooter with one hand. However, in the previous episode, "The Butter Shave," George runs carrying the scooter with both hands, and is clearly holding it with both hands when he runs into his boss.
When Jerry discovers that Elaine slept with Puddy, he tells her that that deems them back together. She denies it, but Jerry strengthens his case when Elaine reveals that they also went out for dinner together. Then, the next time Elaine sees Jerry, he asks for his money, and she says that she won't pay because she's breaking up with Puddy again. However, she should still have to pay him. The bet was that they'd get back together, not that they'd break up again immediately afterwards.
Jerry explains that he's throwing out his belt because it hit the side of a urinal as he unbuckled it. However, it isn't necessary to unbuckle one's belt when using a urinal.
The outside of Jerry's building is shown, and it's clearly nighttime, and then Jerry and Claire are shown going to sleep. But then, after Darren, and then Kramer enter Jerry's apartment during Jerry's fight with Claire, Darren yells to Kramer that the NYU dean is on the phone. Why would a university dean call a business office (Kramerica) so late at night?
When they're about to push the ball of oil out the window, Kramer makes a comment to Darren about how they're about to solve the world's energy problems. Seeing as how they're trying to develop a system to prevent maritime oil spills, shouldn't he say that they're about to solve a major environmental problem?
Goof: When Kramer explains to Jerry why he's started using butter on his face, he keeps waving the stick of butter in his hands around. At the end of the stick you can see something brown-ish, his makeup that has rubbed off. The makeup also rubs off on the slices of bread Jerry smears on his face.
The song "My Baby Takes the Morning Train" by Sheena Easton, was also used in the movie "Euro Trip", which was also produced and written by Alec Berg, David Mandel and Jeff Schaffer.
Jerry: (As George enters the club with a cane) No more crutches?
Actually, in the opening scene in Monk's where Jerry and George are sporting moustaches, George has his cane beside him in the booth, so Jerry must have already known that George was no longer using crutches.
Although he speaks with an accent the whole episode, "Vegetable Lasagna" clearly has no accent when he delivers the line "I can hear you."
How does a flight from Oslo to New York take 22 hours? Even with a stopover in London, the maximum a flight would take would be around 10 hours! It takes 22 hours to fly from the USA to Australia!
If you look at the awning outside Jerry's building; the building's name "The Shelley" has been painted over to hide the fact that it's filmed in California not New York City.