Plot hole: The protagonist gets in the exclusive, multi-millionaire, invites-only auction because the invitation is on a printed letter that he faked. This means that the guards at the entrance don't have a guest list to check, and since nobody knows who this person is, the staff does run a background check on his identity when he makes the first outrageous bid...by looking his name up on Wikipedia. That's mighty low standards of security, especially for an auction that was supposed to be for a selected audience and the most important in France.
The Importance of Not Being Too Earnest - S6-E3
Continuity mistake: When Joey accesses her email address book to send an email to Dawson, she inadvertently hits the address above his, sending her email to the entire Worthington campus. Dawson's email address in Joey's address book is DawsonLeery@worthington.edu. Dawson does not go to Worthington and would not have a campus email account.
Plot hole: Throughout the show it is reported several times that Billy and Ally met when they were both eight years old in a park by sniffing each other's bottoms. However, when Billy is buried in season 3 his tombstone reads, 1968-2000, making him 32 years old. Ally is only 29 and does not turn 30 until later in that season which would at the very least, put them 2 years apart. (00:41:15)
Continuity mistake: In the first episode of season 10, when Marissa is holding a dog while talking to Elaine, the way her arm lies around the dog's neck changes several times between shots.
Visible crew/equipment: After taking the enzyme, Mckay is talking to himself as he dials the gate. When he goes to push the centre button, an arm moves on the opposite side of the DHD. (00:09:35)
Factual error: When Shawn is talking to Belle over the phone, the Eiffel Tower can be seen outside her window, yet, she's supposed to be in Milan, Italy.
Visible crew/equipment: A crew member can be seen to the left of the frame when Eric walks into Simon and Ruthie's room after listening to their conversation about not being punished for leaving the house, and getting lost while trailing the mailman. (00:36:15)
Revealing mistake: Shortly after the fight with Becky, Roseanne asks Jackie to go across the street to get her something to drink, so she can smoke in secret. After Roseanne lights the cigarette and walks near the register, Jackie's plaid coat can be seen in the door's window as she waits for the next scene.
Burning Down the House - S9-E19
Visible crew/equipment: During the scene where Mimi has moved into the warehouse, Drew makes a comment about the TV having surround sound - as the camera pans over him you can see a crew member in the background adjusting a light.
Continuity mistake: When Silas is painting the wall green, some parts jump from being painted to unpainted between shots.
Character mistake: Trivette hands the man in yellow a bullet recovered from the plane Walker and Alex were traveling on, which was shot down by an assassin flying a P-51 Mustang. This man, and later Trivette, mistakenly refer to the round as a "50mm," when in reality, Mustangs were equipped with M2 Browning .50 Caliber (12.7 mm) machine guns. (00:30:25)
Children of Earth: Day One - S3-E1
Revealing mistake: When the children are possessed by the 456, they're supposed to be frozen and stare blankly ahead. But during the second possession, as the camera is panning across a school playground, a boy on the far right is looking directly at it. As it moves closer to him, he swivels his eyes back to where they're supposed to be. (00:16:30)
Other mistake: Jack follows J. Edison Nash to a wine warehouse and watches as Nash punches numbers on a keypad in order to gain entrance to a private room. Nash punches the 6 and a beep is heard. He then punches the 8 and another beep is heard. During a close-up of Jack, four more beeps are heard, for a total of six. Jack says the number out loud - 862, which is only three digits.
Visible crew/equipment: At the mill, when John tells Buck that Willie Brimmer might be at the Montgomery cabin with Jim-Bob, in the next closeup of John we see a billowy trail of cigarette smoke at the bottom right corner of the screen, but the only people standing there are Elizabeth, John, and Buck, and none are smoking. Presumably, it was someone offscreen smoking too close to the camera (similar to a mistake in 1978's "Halloween"). (00:26:05)
Other mistake: With power out Magnum somehow lights the gas stove with the knob, which is electric. Should have used a match. (00:26:40)
See One. Do One. Teach One - S1-E1
Revealing mistake: When they find victim #2 in the woods covered in leaves, in almost every shot of her you can see her breathing - leaves moving up and down. In the closeup of her neck, you can see her swallow.
Lady Killer - S3-E3
Continuity mistake: Root shoots the hitman, walks up to him and slides his gun a couple of feet away. A wide shot shows the gun where it should be. After she says "you're the boss" and starts walking away, we see exactly the same angle, the gun has vanished, and some random black bits have appeared.
Continuity mistake: When the kids are running around, Carmen gets pushed into the mud twice, with no time to stand up, and Toby gets pushed into the mud 3 times, again with no time to stand up. (00:04:15)
Continuity mistake: When the load of lumber is dropped on Captain Greer's 1968 Ford Galaxy 500, the car turns into a beat-up 1960 Oldsmobile just before it is squashed.
Continuity mistake: In season 1 Hobbie was 13 and in season 2 he is 10 years old.