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)
Continuity mistake: When Robin and Ted are at the bar planning their weekend away together, the level of beer in the glass next to them goes up and down between shots. (00:10:00)
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.
The Scorpion and the Toad - S2-E2
Continuity mistake: In the scene where Lily and Marshall are talking outside the bar, the same extra (a guy in a blue plaid shirt with a denim shirt over the top) walks past Lily twice, going in the same direction both times.
Continuity mistake: During the scene in "Marshall and Lily's part", after they leave the bathroom, we can see Robin and Virginia (Ted's Mom) talking in the back. Their hand motions do not match the later scene of the "Robin and Ted's part". Obviously, they were shot separately.
Continuity mistake: When Robin and Lily are talking in the apartment of Barney's date, Lily's hand moves instantly between shots from resting on her shoulder, to resting on the handbag by her side.
Continuity mistake: When Barney is in the Professor's office, we see the professor put a red pen down on her desk and her hands are then empty. In the next shot, she suddenly has a blue pen in her hand.
Continuity mistake: When the gang are drinking a toast to Ted at the end of the episode, Robin's glass of champagne moves from her left to her right hand instantly when the camera angle changes.
Continuity mistake: When Lily, Ted and Robin are at the bar discussing Ted's building design, Lily's drink keeps moving between shots. Sometimes it is in her hand lifted towards her mouth, whilst in other shots it sits on the table.
Continuity mistake: When Marshall and Lily approach the reception desk at The Wedding chapel, Marshall's cocktail moves from his right to his left hand instantly between shots. (00:07:55)
Continuity mistake: At the courthouse, we see Marshall, Lily and Barney walk around the corner towards the bench twice, from two different angles.
Continuity mistake: At the courthouse, when Lily is eating red licorice from the vending machine, the piece she is eating gets longer between shots.
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.
Continuity mistake: At the apartment when Marshall gives Lily the red cocktail, the green paper umbrella moves from facing away from Lily to facing towards her between shots.
How Lily Stole Christmas - S2-E11
Continuity mistake: When Ted, Robin and Barney are having a meal at the bar, we see Robin lift her drink to her mouth, then the shot changes to another angle and we see her lift the drink again.
How Lily Stole Christmas - S2-E11
Continuity mistake: When Ted, Robin and Barney are at the bar, discussing the fact that Barney is ill, the level of the drink in Robin's glass goes up and down between shots.
How Lily Stole Christmas - S2-E11
Continuity mistake: When Marshall and Ted are on the phone to one another, the string from Ted's hoodie changes position between shots, much of this may be because he is moving his hand due to being on the phone. However the right string goes back and forth from being caught on the collar of his jacket to hanging straight down over his jacket just before he is on the phone to his mother.
First Time In New York - S2-E12
Continuity mistake: During Ted's second flashback to how he lost his virginity to Molly (the real story), as Molly gets out of bed you can see she's already wearing pants, but after we cut she stands up and starts putting them on.
Chosen answer: She was finally shown at the very end of the last episode of season 8, continuing into season 9. The actor's name is Cristin Milioti: http://www.imdb.com/name/nm2129662/.
Knever