Factual error: When Bart is at Nelson's house and Nelson is firing the BB gun, bullets should come out of his gun when he pumps it. None ever come out, and several times he is shown firing without pumping.
Sunday, Cruddy Sunday - S10-E12
Factual error: At the end, when Homer and company are being carried out of the Super Bowl after the game, it is daylight. Usually, it is dark by the 4th quarter.
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.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.