The Old Man and the C Student - S10-E20
Audio problem: At the end of the episode, Grampa's mouth doesn't move when he sings.
Monty Can't Buy Me Love - S10-E21
Continuity mistake: Ralph Wiggum is seen riding the train inside the mall, but is seen some seconds later amongst the crowd of people still waiting to enter the store.
Monty Can't Buy Me Love - S10-E21
Continuity mistake: Bart is next to Homer when Marge says "Where did you get that champagne?", but in the next shot, a clown is in the spot Bart was.
They Saved Lisa's Brain - S10-E22
Character mistake: The plural form of ignoramus is ignoramuses, not ignorami. The word "ignoramus," a Latin verb-form meaning "we do not know," has no Latin plural-noun form. Therefore, when used as an English noun it correctly pluralizes as "ignoramuses." Someone as smart as Lisa should know this.
Thirty Minutes Over Tokyo - S10-E23
Continuity mistake: Marge loses one of her shoes in the "lava" , but when they fall down, Marge wears two shoes again.
Thirty Minutes Over Tokyo - S10-E23
Continuity mistake: When Homer breaks into Flanders's house there's a shot of the refrigerator and nothing is on it. In a closer shot, there are tickets being held up by a magnet.
Thirty Minutes Over Tokyo - S10-E23
Factual error: There is a flight to Honalulu, Hawaii listed on the national flights screen. This is a domestic flight, as it does not involve leaving the country.
Thirty Minutes Over Tokyo - S10-E23
Continuity mistake: When Database is at The Java Server, he is using a teal computer, but when Snake comes in, he is using an orange computer, then he is using a teal computer again.
Thirty Minutes Over Tokyo - S10-E23
Continuity mistake: When Lisa gets the tickets on the "volcano", she is a few inches away from the end of the bridge. When it falls and Marge runs onto the bridge, she is now in the middle of it.
Thirty Minutes Over Tokyo - S10-E23
Audio problem: In America Town, when Bart says "These prices suck. 10,000 Yen for coleslaw?", his mouth doesn't match what he is saying.
Revealing mistake: When Homer is giving Marge, Lisa and Bart money, Homer puts his hand on Bart's shoulder and whispers 'Mel's movie really stinks'. When he lets go of Bart to say this, he leaves his fingers on Bart's shoulder, but he still has fingers on his hand.
Other mistake: When the Simpsons' drives the electaurus off the edge of the harbour, it is shown that The Front of the car goes downwards. When it cuts to the interior view with the Simpsons' screaming, the view from the back window is tilting down, suggesting the rear is going down and The Front coming up. But in the next shot the car is seen in the water with The Front down.
Continuity mistake: The "dummy" in the episode changes consistently from a real character to a dummy sometimes. When Mel jumps into the vehicle in the museum the "dummy" moves aside. When Mel shoves it out of the way, it stays in one rigid position as if it is a dummy. During the chase, the "dummy" falls on the car behind and its facial expression changes. But when one of the guys from THAT car (not the one Mel was in) goes to the dummy, its head is ripped off and you can see that it is stuffed.
Continuity mistake: The text on the billboard which says "She's having a baby...again!" is black when Mel Gibson and Homer crash through it. After they have landed on the ground, the text on the billboard is white.
Brother's Little Helper - S11-E2
Continuity mistake: When Homer and Marge are in the research lab, the scientist pulls off a white cloth which is covering the hamster tank and places a tube next to it, but in the next shot it's gone. (00:04:55)
Brother's Little Helper - S11-E2
Audio problem: Homer's mouth is out of sync when he's naming celebrities who use drugs.
Guess Who's Coming to Criticize Dinner - S11-E3
Continuity mistake: When all the people who are plotting to murder Homer are talking about the reviews Homer had given them, Akira says, "So why did you put yours in the window?" and you see the review. At the end of that scene, when they are all laughing, you see the building they are in, and it has nothing in the window.
Guess Who's Coming to Criticize Dinner - S11-E3
Other mistake: In the German version, the Italian cook peeved by Homer's comment on lasagna swings the cleaver at him using an Italian word ("Porcodio") which is a rather strong blasphemy, way stronger than any other expression used in original or in other localizations worldwide.
Tree House of Horror X - S11-E4
Revealing mistake: When Bart tells Lisa, 'Must have given you super strength,' Bart's arm is not fully coloured red and partially takes the colour of the floor from the background. (00:08:25)
Tree House of Horror X - S11-E4
Continuity mistake: The broken railing in front of Lucy Lawless returns to normal when the shot changes after the Collector lands on the computer.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.