When Monique is throwing fruit at the sign she is only slightly bending over to pick up the fruit. When we see her from further away, the fruit is on the ground - at a height level much lower than to which she stoops to pick them up. When we see her closer again in the next shot to throw more fruit, she is only stooping half way again.
The math teacher tells Lane to show the class his solution to the "paltry geometric dilemma". A dilemma is a difficult decision - math problems can't have dilemmas, because they can't think. The correct word would be "conundrum".
When Lane and Monique roll up to the Ree brothers (and their dates) in the Camero and as soon as they realize he's there, they scramble to put helmets on. The female riding shotgun puts her helmet on backwards covering her eyes, then adjusts it so that she can see. It remains on backwards until she takes it off to hit the driver with it.
The family's name is "Myer." This spelling is used in the end credits and in all promotional material for the movie. But Badger gets a package in the mail, and on said package, the family name is spelled as "Meyers."
Lane trips on the skates and accidentally pulls Chris' cheerleader outfit down around her ankles, exposing her underwear-clad body to the cafeteria. In the next shot that shows the outfit, it is away from her body, closer to lane, not near her feet. If Lane had actually pulled the outfit out from under her skate-clad feet, she would have tripped.
During the scene when Monique and Lane are in his garage working on his car, the lettering on the tires change positions in each shot such that the tire manufacturer name on the tires are always visible. The tires appear to have been turned between each shot to make sure the manufacturer's name for product placement appears correctly.
After Lane and Monique ski all the way down the mountain, starting from the top of the K12, Lane skis away to escape from Johnny the paperboy. He emerges back at the top of the mountain in time to race - apparently having skied back up the mountain, with Johnny continuing to follow.
As Lane and Monique, in the newly-fixed Camaro, drive up to the car with the Ree brothers and their dates, the wide shot shows the foursome noticing and looking over at the Camaro. However, in the next shot they are still chatting amongst themselves and haven't seen the Camaro yet.
Lane in sitting in class and pulls a folded piece of paper out of his pocket. It is clearly wrinkled and has a wad of gum in the middle. Later, he holds up the piece of paper, smooth and no sign of gum.
When Lane passes out at the wheel of the car in the garage, he slumps over with his head against the steering wheel, but when the car crashes through the door and backs down the driveway, the driver's head can be seen as though he is sitting straight up.
When Monique knocks Lane down, as he gets up, he says, "You're that French kid staying with the dorkheads, uhh.. Smiths next door." However, it seems apparent in a later shot (when Monique is throwing oranges) that the Smiths actually live across the street.
The number of plates jumps from three to one between two shots, both of which contain Mrs. Meyers in the slime dinner scene. Also, even though her hands are never out of the camera's view throughout the entire serving, she is never shown serving herself and yet has a full plate.
When Badger (Lane's younger brother) receives the package, the address is in fact the address of the house which was filmed in Glendale (see filming locations) but the ZIP(TM) code shown is 93065 which is the ZIP(TM)(postal) code for Simi Valley, California.
When Monique is working on Lane's car, we see various parts lying on the ground in the opening shot. She shows Lane she has gotten his car running, despite the fact one of the parts is the distributor, which is necessary for the car to start or run.
(at 54:05)When Rocko (Chuck Mitchell) issues the keys to Lane (John Cusack) he tells him that he wants him in there at 6:00 to sweep and mop for the breakfast crew. Restaurants routinely do so at night while closing, so the place would be swept and mopped Friday night (or any other night for that matter).
At the final race, the race official signals Lane to go first. The official then sends Roy 5 seconds later, thus suggesting that the race is based on time. Lane beats Roy by only a fraction of a second. Therefore, Roy had the better time and should have won the race.
1:13:27 Lane Meyer is talking to Monique while she is working on the Camaro. The coffee cup reads, "Larry". Nobody in the Meyer household is named Larry. Lane's father's name is Al, and his brother is Badger, and his mother is Jenny.
On Christmas morning, Al Meyer is putting a bow on the garage door, he is using a ladder. However, when he stands on the driveway in front of the garage, he is eye-level with the bow. Clearly, he did not need the ladder to put either the windows in or the bow on. Exactly, that's the joke.
Charles DeMar (Curtis Armstrong) says to Lane Meyer (John Cusack) at the end of the algebra class, "if you make that run girls will get sterile just looking at you". Sterile is a male trait. Women can become infertile, but it's men who can get sterile. Charles isn't very bright (he remarked that he had been going to high school for seven and a half years), so a mistake like this on his part is not out of character.
When Lane is getting ready for his date with Joanne Greenwald and he starts spraying deodorant, as he lowers the can below the bottom of the mirror, you can see two streams of deodorant. The smaller is from the can Lane is holding, and the huge one is from something out of the sight of the camera.
When the paperboy is chasing Lane and Roy down the mountain you can hear the card in the spokes on his bike making noise. That is not possible. The wheels aren't turning because they are mounted on skis.
In the opening minutes after Al gets the rolled up newspaper that was thrown, he stands in the kitchen and talks about it being Sunday, but in the earlier scene showing the paper being thrown, it was obviously a weekday edition - much smaller than a Sunday edition.
When Lane's father is reading the book on teenage drug use, the camera focuses in on the headline of the chapter: "Paranoia". The first two lines of the chapter are visible & are obviously "Greeked" or made-up nonsense text.