Continuity mistake: In the scene after Joey draws the penis on the guy's face, the penis drawing gets darker and more defined between when Joey initially drew it and the next.
Continuity mistake: When Cameron's friend is putting on his helmet before he goes on the motorbike you can clearly see the goggles strap over the helmet. He gets on his bike and is run off the cliff but after he gets up the strap is nowhere to be seen but his goggles are still on.
Continuity mistake: During the prom scene Save Ferris is playing 'I Know'; it switches from the middle back to the beginning and then the end of the song over the course of the scene.
Continuity mistake: In the second scene where Cameron and Michael are talking to Pat in the shop, Pat puts down a bunch of triangles onto a glass surface. When the camera changes shots, he suddenly has more triangles in his hand, and he puts them down again.
Continuity mistake: When Michael is on his scooter, his goggles are up on his helmet, but a split second later when he pulls up to Cameron, the goggles are on his face. It's all one continuous sequence and he's in shot the whole time - there's no chance for him to pull them down without us seeing.
Continuity mistake: When Patrick is singing to Kat, while the band is playing he can be seen dancing behind a girl in a blue shirt sitting down. The camera cuts to the band and back to Patrick when he starts to sing but this time he's near a group of guys who are in front of a red flag. The camera then cuts to Kat and then back to Patrick who is back with the girl in the blue shirt - this time he's next to her rather than behind her. A few seconds later you can catch a glimpse of the girl and the guys both behind Patrick in their same respective spots which are nowhere near each other (the girl being further down from the guys).
Continuity mistake: When Patrick sings to Kat during her soccer practice, after the band does their solo and Patrick begins to sing again, the camera shows a close up of Kat in which her teammates follow closely behind her. The camera goes back to Patrick then back to Kat, this time her teammates are still following her but they are further back. After another flip to Patrick the camera flips back to the girls who are back where they were the first time.
Continuity mistake: In the scene where the teacher asks Kat why the school can't buy a book "written by a black man." the white Rastas are next to and slightly in front of the teacher as they raise their fists in support, yet as the camera switches to the front view, the teacher is in front of the class and they are at least ten feet away.
Continuity mistake: In the classroom where the students are dissecting frogs, the camera is showing a close up of Cameron and Michael talking and in the background you can see Patrick take out his tool to stab the frog. Then the camera immediately goes to a close up of him and he re-takes out the tool and actually stabs it.