Continuity mistake: During the scene back in college, when Marshall and Lily are listening to Dr. X's show, at the first shot of the radio, you can see some popcorn there already, although Marshall has not thrown any, yet. Even if you claim he's been throwing constantly, a few shots later they vanish, and reappear.
Continuity mistake: At the third party when Lily sits Ted down to talk to him, Marshall stands behind Ted with a beer bottle in his hand. The position of Marshall's hands on Ted's back changes between shots. (00:14:40)
Intervention - S4-E4
Revealing mistake: When the encyclopaedia bookshelf falls off the wall in the flashback, you can see the wall being pushed out, showing that it was being manipulated from the other side by crew.
Sweet Taste of Liberty - S1-E3
Continuity mistake: When Marshall is on the phone to Barney, the green highlighter jumps back and forth from on the desk to on top of the open book.
Continuity mistake: After Ted's Saturday night party (second of the three), when Ted, Lily and Marshall are sitting on the couch, numerous things change or suddenly appear behind them. Clothing is instantly on the back of the yellow chair and black chair, a wood chair appears, furniture moves, etc.
Continuity mistake: In 5-22 "Robots Vs Wrestlers" future Ted narrates, " No matter if we fell out of the group, we always made it to Robots Vs Wrestlers. Hell or high water." In this episode, Ted is the only one who goes.
The Wedding - S1-E12
Other mistake: On The Wedding invitation it says the year is 2005, when it should be 2006 since the last episode was New Years.
Continuity mistake: When Robin buys Lily's "favorite dress", Lily holds it on her lap folded, when the camera changes angles it is unfolded.
Factual error: A shot zooms out to show a powerful storm system just offshore from the eastern seaboard. However, the cyclonic storm system is rotating clockwise, while low pressure systems in the Northern Hemisphere rotate counterclockwise.
Continuity mistake: Before Marshall proposes the gold foil is still on the bottle of champagne. He sets it down with the foil still on and they have sex on the kitchen floor. When they sit up, he grabs the bottle of champagne again and the foil is already off. (00:04:50)
Symphony of Illumination - S7-E12
Revealing mistake: While Marshall is on the roof putting up Christmas lights he accidentally drops his cell phone, which supposedly then falls to the ground where Scott picks it up and holds him hostage on the roof. But the cell phone can be seen to fall harmlessly into the gutter and can be seen behind the ladder, despite the added sound of it hitting the ground. (00:10:45)
Continuity mistake: There is a lot of foam in the glasses when Barney pours champagne, however after camera shot changes all the foam is gone. (00:10:15)
First Time In New York - S2-E12
Continuity mistake: At the airport, Lily and Robin are talking off to the side away from others. During the scene, the cameras shoot from in front of the two actors and from behind Lily. From the frontal view, Lily's two headbands are white and gold-jeweled. The white headband is closest to her forehead. When the camera shot switches from front to behind, the headbands are switched on her head. The gold one is now closest to her forehead and the white one is behind.
Suggested correction: If you look closely, you can see that the headband is actually symmetrical, so the black strap is on top and in the middle of a larger white headband and never changes. (camera angle makes it often seem both from the front as from the back as if there is no white part behind the black).
Continuity mistake: Barney blocks Ted's path by standing in front of the door. Watch his position as he says, "Ted, don't do this" for the second time, he has his right arm over his head. When the camera changes angles he has it down.
Continuity mistake: In the scene at the hotel bar, the red straws lying on the table next to Ted change position between shots without being touched.
Continuity mistake: In the scene at the bar where Robin is describing looking after Marshall as being like having a baby, Barney's drink moves from in his hands to on the table and back again instantly between shots. (00:06:30)
Life Among the Gorillas - S1-E17
Continuity mistake: At the karaoke bar, when Marshall is deciding which song to sing, his beer bottle keeps switching hands between shots.
Continuity mistake: When Robin and Barney meet up for drinks, the amount of ash on the end of Barney's cigar goes up and down frequently between shots. (00:06:10)
Continuity mistake: When Lily drops the potato chips on top of the 'salad', we can see a few chips sticking up beyond the top of the bowl. The shot changes and now the chips are laid flat, with none sticking up over the top. (00:07:40)
