Sweet Taste of Liberty - S1-E3
Revealing mistake: Barney tells the cab driver to lock the doors, and he does. We then see Ted trying to open the door and you can hear the taxi is still driving by the engine noise. However, the scenery outside the windows has stopped moving. (00:01:50)
Continuity mistake: When Barney is scoping the apartment, his hands are next to his temples. As the shot changes to a wider shot, they are now much further away from his temple. (00:08:05)
Continuity mistake: When Barney is explaining about there always being 1 girl who doesn't know who's party it is, his hand is sudden;y outstretched or by his side depending on the shot. (00:08:00)
The Best Burger in New York - S4-E2
Continuity mistake: When Ted picks up his burger it already has a bite taken out of it, then in the next shot the burger is whole again. (00:20:09)
Continuity mistake: After telling the joke about the Teenage Mutant Ninja Turtles, Marshall's hands change between shots, from holding his hand for a hi-five to his pockets to holding the Skittles. (00:08:32)
Character mistake: In another episode it is revealed that Robin hates nicknames and reacts badly when she, or anyone else, is given a nickname. However, in this episode her and Marshall give each other nicknames, and she doesn't seem bothered at all.
Continuity mistake: When they are watching the music video on the small screen on the table, there is a bottle of JT Cola next to the screen in the close ups. When it goes to a wide shot, it is suddenly replaced by a beer bottle. However, in the previous shot before the commercial break it is a JT Cola bottle in the same spot as the beer bottle.
Factual error: When Ted recalls his trip to Spain the map onscreen is full of spelling and geographical errors: Marida appears in Portugal but it's in Spain and should be spelled Mérida. Valencenia = Valencia; Tarrogona = Tarragona; Grenada = Granada; Pamplona is placed where the city of Bilbao is; also Sevilla is placed 140 kilometers to the left of where it really is.
Continuity mistake: Randy's noise bleed moves from his left nostril to his right and then back again. (00:14:20 - 00:15:00)
Continuity mistake: When Ted sits down to talk with Hammond Druthers after discovering that Druthers is living at the office, Hammond pours them both a J. Buckley whiskey. When Hammond places the bottle down the label is facing towards Ted. The camera then swaps to Ted and upon swapping back to Hammond, the label is facing away from Ted. Hammond is describing his wife as "quite mannish." The camera swaps to Ted. Upon swapping back to Hammond, when he continues with "She gives me what I need", the bottle has been rotated so that the label faces towards Ted again. (00:11:40)
Continuity mistake: When Lily is talking about how much of a badass she used to be, it shows her meeting Scooter. He said his name was Jeff, but in season 9 Lily says that Scooter's real name is Bill. (00:03:40)
Factual error: When Barney puts the CD in Marshal's laptop it's upside down but works. Barney points the label which has writing on it towards the camera as he puts it in the laptop.
Continuity mistake: When they call Barney to find out if he succeeded with The Naked Man, the girl answers the phone. In that shot Barney's tie is curled up next to the shirt, but in the next shot, the tie lies on the shirt. (00:19:00)
The Scorpion and the Toad - S2-E2
Audio problem: When Lily is talking about finding her passion, as she says "music" the audio doesn't match her mouth. (00:07:50)
Nothing Good Happens After 2 A.M. - S1-E18
Visible crew/equipment: When Robin hands Ted the glass of wine, you can see set lights reflected in the glass. (00:10:55)
The Chain Of Screaming - S3-E15
Character mistake: Marshall, especially as a lawyer, should have known that simply screaming "I QUIT" towards his boss wasn't official resigning. He would have to write a notice letter with his signature in order for his resignation to become official.