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)
Intervention - S4-E4
Continuity mistake: After the gang gets to the bar around the end of the episode, Ted starts his speech about how they all need to move on. As he moves over to the booth, he tells the people sitting there to get out. You can see that the girl takes her phone with her, and there is no other phone anywhere on the table. A few seconds later, she comes back saying that she left her phone, and now the phone is visible on the table. (00:19:25)
Intervention - S4-E4
Continuity mistake: In this episode, both Ted and Marshall mention that Lucy, Stella's daughter, is 7 years old, when in the previous season (13th episode of 3rd season, Ten Sessions) Stella states: "I have a daughter. Her name is Lucy, she's 8." Did she grow younger?
Intervention - S4-E4
Revealing mistake: In the flashback when Ted damages the ceiling beam with the flail, you can see that the damage is already there before Ted actually hits it.
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.
Intervention - S4-E4
Continuity mistake: In this episode we see that Barney punched a hole in the wall next to the door because Ted broke apart a girl fight. It is supposed to be under the calendar on the right side of the door. It is also said that Ted and Robin were dating at this time. But earlier, in the episode "Wait For It..." (3-1) We see Ted going through his break up phase after Robin. One of the phases is painting the apartment, and there is no hole.
Continuity mistake: Robin says she never played any team sports in 1-6 "Slutty Pumpkin". But in this episode she talks about her relationship with her father, being on a hockey team that won a championship and she made out with her teammate.
Revealing mistake: In the front shot of Ted in front of Stella's apartment, it is painfully obvious that he is in front of a green screen and not actually on a street.
Other mistake: At the end, on the steps in front of Stella's apartment, Stella's daughter stares at the camera for half the shot.
Continuity mistake: When Lily is making her list she takes the lid off the pen twice. (00:09:00)
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)
Audio problem: When the woman catches Barney doing The Naked Man, she yells at him to get out. After Barney says "Just have to grab my suit, it's very expensive", she says "Get out!" twice. When she says it the second time, she quickly turns her head and her mouth doesn't seem to move with the audio. (00:19:10)
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: 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.
Other mistake: At the start of the episode it can be seen that the DVD player only has a power cord connected. Shortly afterwards only one cable (power) is seen connected to the TV set, then a few seconds later Ted plays a DVD.
Chosen answer: In a flash forward scene in Season 8, it shows him with his first born: a daughter.
XIII