There's Something About Mary (1998) - 36 mistakes

Continuity: The crowd that watches the guy fight with Warren and Ted near the beginning keeps on changing. People move where they're standing between shots and the arrangment of the crowd changes throughout the scene between shots too.

Continuity: When Mary says to Ted "I have a lot of fun with him" about Warren, her hair falls over her eye. In the next shot it is pushed back.

Factual error: Ben Stiller takes Cameron Diaz to the prom in 1985, but picks her up in a car made well after that; it has the newer-style headlamps.

Audio problem: When Mrs. Jenson see's Ted's thing caught in his zipper, she turns and yells "Holy Shit!" Her lips however don't reflect these heard words.

Continuity: When Ben Stiller got his "frank and beans" caught in the zipper, the friendly police officer thought he would assist with the problem. He unbuttoned his sleeves and rolled them up, but then the next camera shot showed them buttoned up, and had to be rolled up again.

Continuity: When Pat is spying on Mary, the first morning he spies on her, Mary leaves her house and walks down to a deck and she throws Herb an apple. In a wide shot, on the barrel next to Herb is a cup, yet in the following closeup a bottle of whisky appears from nowhere.

Continuity: When Mary has lunch with three friends, in a wide shot one of her friends picks up her drink and brings it to face level. In the following closeup of her, she brings the drink to her face again.

Visible crew/equipment: When Mary is having lunch with her three friends and she is talking about the kind of guy she wants to meet, you can see the boom mic in the reflection of her sunglasses.

Continuity: When Ted is laying in bed, he gets up and pushes his blue and red sleeping bags further down the bed, just before taking his picture of Mary out of his wallet. Between shots the position of the sleeping bags changes greatly.

Continuity: When we see the first shot of the meeting Dom is holding, you can see the meeting table with loads of sheets on it. Then it changes to a shot of Dom standing by his big pad (just before Ted runs and yells "Mary's a fox!"), and the sheets on the table have moved around and some have vanished.

Continuity: When Pat is round Mary's, he is holding the dog. Between a wideshot and closeup, the way he holds the dog changes.

Continuity: When the dog is dead, Pat tries to revive it by using some wires. When it fails, he puts the wires on the couch then peeks into the kitchen to see what Mary and Magda are up to. Then in the next closeup of the dog, the wires how moved to laying on his stomach.

Continuity: When the dog is on fire, Pat gets a vase of water and pours it on the dog. In a wide shot the dog is on it's back, with all fours pointed up in the air. Yet in the closeup of the water being poured on the dog, the dog is on it's stomach just sitting down properly. This is obviously due to the switch of the fake dog to the real dog.

Continuity: In the scene at the fairground, Cameron Diaz is holding a stick of very abundant cotton candy. The camera pans away for a few seconds, and when it returns the cotton candy is almost completely finished.

Revealing: When the investigator takes Ted's head and starts slamming it on the table after Ted got finished telling them about the hitchhiker, Ted's head never hits the table but his own hand.

Continuity: About one hour into this movie, when Healy is playing tag with the 'Neary group people' he goes for the touch down and Warren runs after him to get the ball. As Warren first dives for the ball, you can see that he has three red tags attached to his back, in the next shot as he lands you can see that the tags have disappeared.

Visible crew/equipment: When Ted and Dom are looking at Mary, speaking with Warren and Tad from behind the tree, if you look carefully you can see the camera and crew in the reflection in Ted's glasses.

Continuity: This is during the scene on the outside steps of Mary's office, when Mary and Ted see each other for the first time. A suit-wearing businessman comes from the left side of the screen behind Mary twice. This happens when Mary is saying "Ted? Is...Is that you?" and the camera goes back and forth between Ted and Mary.

Continuity: When Ted sees Mary for the first time in years, the hood on his sweatshirt changes from his back to his right shoulder.

Revealing: When Puffy the dog bites Ted and pulls him along, Ted digs his fingermails into the floor, they scrape along, making marks. If you look very closely you can see faint pre-made marks made in the floor, where he drags his nails along.