Corrected entry: This episode takes place during the holidays and Robin is missing her family. At the very end of the episode Robin and Marshall are sitting outside - Robin is eating an ice cream cone and Marshall is drinking an icee, and they are both wearing T-shirts. Behind them are poinsettia plants and they mention Christmas in the episode. They live in New York. It snows in New York during the holidays or is at least cold. They would not be wearing T-shirts sitting outside on the stoop eating ice cream.
Corrected entry: Barney drives fast to prove to his friends that he can talk his way out of a ticket, however in the earlier seasons, when Marshall's car broke down, they tell a story about Barney driving and he cannot drive, and seems to have a fear of driving.
Corrected entry: In Baby Talk, Marshall's father gives him advice on how to conceive boys and avoid conceiving girls, because Marshall's parents had "all boys." However, in the Season 1 episode Belly Full of Turkey, Marshall's sister is a part of the family.
Correction: The character you're referencing is Ashley Eriksen, which would be Marshall's brother Marvin's wife, Marshall's sister in law.
Corrected entry: When Ted, Barney and Robin are sitting at the bar with Liddy (The Wedding planner) she hands them a catering menu. Barney's is sideways yet you see him use his finger to "pretend" read it and scroll through it.
Correction: Neil Patrick Harris is absolutely doing this intentionally, to enhance the point that Barney is not paying any attention to the menu. Ted and Barney are preoccupied with trying to get Liddy to take her coat off so they can see her "redonkulous" body, as Ted put it. Barney is not paying attention to the menu. This falls right in line with how Barney always acts in similar situations. Furthermore, if you look closely, Robin's hand pointing out to him that he's holding the menu sideways, but he's too focused on Liddy to notice this.
Blitzgiving - S6-E10
Corrected entry: When Ted is explaining the curse of the blitz, they are all shown at the bar. But the blitz guy says he is going to leave because he just got Madden 2k1. If it's 2001, why is Robin in the shot? They didn't know her then.
Corrected entry: In season 1 Ted buys the English phone booth when he starts freaking out about Lily moving into the apartment, but in this episode he tells Robin that he got it from a previous girlfriend.
Correction: The phone booth Ted buys is a life size version. You don't see it in the apartment after that episode. The one Ted got from a girlfriend is a miniature version (like a statue).
The Exploding Meatball Sub - S6-E20
Corrected entry: When Marshall is unable to join him for lunch and Barney trashes his office, paper rains down from above when he never actually threw paper up into the air.
Correction: Actually he does throw paper up. It happens very quickly, but it's there.
The Chain Of Screaming - S3-E15
Corrected entry: Barney says that Gary Blauman died, but in season 9, Gary Blauman is a significant character.
Correction: Barney was lying, it's as simple as that.
Corrected entry: When Ted meets Victoria in season 1, he plays the piano for her (well) while she tap dances. In this episode it explains that that Ted was taking piano lessons to do a performance at The Rehearsal Dinner and he is terrible.
Corrected entry: When Ted is telling Lily and Marshall about him and Victoria stealing the bouquet, Lily says "Good for Victoria", even though they don't know her name yet. (00:05:30)
Corrected entry: In S1E06 Lily dresses like a parrot and Marshal like a pirate. At 5 min 03 sec. Lily says that she needs to pee and Marshal goes with her because she wears an elaborate costume. Later in S1E14 Marshal and Lily are trapped in their bathroom because Ted and Victoria are trying to do it in the living room and they do not know that Lily and Marshal are at home. After a while being trapped Lily says that she wants to do something she's never done before, i.e. she wants to pee while Marshal is also in the bathroom.
Correction: Marshal may well have helped her out of the parrot costume, then left the bathroom while she used the toilet. He could then return to help her back into the costume.
Corrected entry: Once Lily finds out Marshall has accepted the judgeship, she is brought a drink and reveals to the group, "yes this has booze in it, no it's not my first." However, later in the season we find out Lily was drinking non alcoholic drinks the entire time because she believed she was pregnant. (00:01:50)
Correction: Or she just lied to keep people from assuming she's pregnant? Pretty sure this isn't a mistake and that it's just a lie Lily told the group.
There was no reason for her to lie though. No one asked her what she was drinking and she just randomly walked up to the group and said she was drinking alcohol.
I agree with the corrector; Lily lied to her friends. She is hanging out with her very best friends that she sees everyday, knows her drinking habits and she is not ready to share news of her possible pregnancy (esp. Before telling Marshall). On top of it, they would be really suspicious if she had a non-alcoholic beverage and she was free as a bird since Marvin was with Marshall. As a person that tried to hide a pregnancy in social settings, I made it known that my coke was a rum and coke (even if no-one asked).
Correction: I think she wants to show how upset she already is, like a "don't mess with me" warning.
Corrected entry: Robin walks into the apartment and sees a goat turd, which can only be there if The Goat was in the apartment. She goes on to talk to Marshall about keeping quiet about the fact that she slept with Barney, so we know that this happened when Ted was turning 30. But later in the end, Ted says that The Goat was actually there on his 31st birthday. So The Goat turd could not have been there at the time.
Correction: This whole show is told in flashback from a guy remembering 10 years previously. It's the type of thing where it's very, very difficult to pinpoint what is a mistake and what would come under remembering, which I think this does. It would only be a plot hole if it meant something else in the series couldn't have happened unless it specifically had to be there on his 30th.
Correction: First, it's more like 20 years in the past (2030 is present and 2005 - 2013 is the past... Ted turned 30 in 2008). Second, Marshall threw 2 surprise parties, the first on Ted's 30th birthday and the second on his 31st birthday. It is totally conceivable that Present Day (Bob Saget) Ted co-mingled the events of two separate birthdays that occurred 22 and 21 years in the past; one where Robin identified The Goat turd (Ted's 31st birthday) and when Robin slept with Barney (Ted's 30th birthday) especially if the focal point in his mind was a surprise birthday party. Finally, that is the point of the end of the episode when Present Day Ted acknowledges that The Goat incident happened the following year so the viewer is meant to disregard any references to The Goat on Ted's 30th birthday.
Corrected entry: When Barney does "Have you met Ted?" for the first time, he taps a woman wearing a red top but you can't see her face. When the camera angle changes to reveal it as Robin, she's wearing a green top. (00:00:43)
Correction: Within the actual episode this does not occur. During the episode (00:02:50) Barney taps the shoulder of the woman wearing a red top standing beside him, and it's Yasmin wearing the red top as she and Ted continue to converse, until Yasmin tells Ted she's Carl's girlfriend. It's later in the episode (00:05:50) that Ted spots Robin wearing a green top, then Robin walks over to the bar counter. It's at this moment where Barney taps Robin's shoulder.
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.
The Wedding - S1-E12
Continuity mistake: In this episode, Lily is in Robin's house with her dogs. In the episode "World's Greatest Couple", Robin reveals that Lily can not stay at her apartment because Lily is allergic to dogs.
Suggested correction: Doesn't mean Lily can't go over and visit for a while. My mother is allergic to cats. She can visit her cat-owning friends for a while, though she would never stay overnight. Pet allergies can be pretty controllable, as long as you're not constantly in contact with the animal.
Other mistake: When Ralph Macchio mocks Barney for not gambling in AC, Barney makes a U-turn to head back, but turns the wheel to the right instead of the left. (00:12:00)
Farhampton - S8-E1
Corrected entry: When forced to explain himself to Quinn in 1 minute after finding out Barney and Robin used to date, Barney incorrectly states that Robin moved to Brazil and came back with "a Latin stud" after Ted and Robin broke up. Robin actually vacationed in Argentina. (00:11:35 - 00:12:40)
Correction: Barney's knowledge of geography is awful, as we've seen throughout the show. So, this could easily be in the script on purpose.
Continuity mistake: Lily and Marshall mention that they've been using the same toothbrush ever since they've been together, but in the 14th episode of the 1st season, "Zip, Zip, Zip", Marshall and Lily are simultaneously brushing their teeth with a tooth brush each (before Ted and Victoria get home). (00:05:05)
Suggested correction: Many people buy another toothbrush to take on trips and since they were supposed to be going away, they probably decided to use them at home, as if this was their trip.
Subway Wars - S6-E4
Revealing mistake: When Ted uses his laptop to get directions to the restaurant, Bing shows Los Angeles (where it's filmed) as their current location, instead of NY where the show is set. (00:02:15)
Suggested correction: Depending on the location settings on his laptop, they could be giving a false reading. My laptop shows I'm in Cardiff Wales while in fact I'm nowhere near.
The show was actually filmed on a film set in Los Angeles which is probably why the laptop says Los Angeles as the current location. This most probably slipped past the editing crew.
Correction: The episode makes repeated references to the fact that they are from colder areas (Canada and Minnesota). As such, neither find the winter climate in New York particularly cold, something that is exaggerated to the point of them behaving as if it is summer weather. It seems you missed one of the key jokes in the episode.