The confetti on the stage during the carnival step-dance varies inconsistently between shots.
During the last quarter of the championship basketball game, the camera shows the scoreboard ticking down to 50 seconds; when the camera pans back later, the scoreboard shows 30 seconds and counting. A few seconds later the camera pans back again and the timer has jumped back up to 50 seconds. Later it shows 23 seconds, then 10 seconds later the scoreboard shows 30 seconds again.
When Kyle and Russell are talking in the cafeteria, Russell eats a potato chip then speaks to Kyle without enough time to chew and swallow it.
When Kyle's alarm rings, the close-up of the clock shows a time of 7:01. When he stops the alarm in the far camera angle, the time is 5:10.
When they are driving home from the basketball game, the streets are wet but the sidewalks are dry.
When Bonnie is shown looking towards Kyle's computer screen in the library scene, it's obvious that the screen is blank.
When Bonnie confronts Kyle while he is trying to make his 10 free-throws in practice, she takes the ball and shoots. The camera makes it look like it goes in, but slowed down the ball misses and the net doesn't move in coordination with the ball.
When Seamus shrinks at the end, his fellow leprechauns start looking down before he actually shrinks.
In the game before the championship, you can see #4 for the opposing team wearing a white undershirt underneath his jersey. A few seconds later, a different actor is now playing #4 with no white undershirt.