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: When the gang is thinking about baby names, Esther is brought up. We then see Marshall and Barney at the strip club where Esther shoots out a bunch of playing cards and one sticks to Barney's forehead. He peels it off and says "That WAS my card!" But he never looked at the face of the card, so he couldn't possibly have known which card it was.
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: Cindy's claim that there is a policy against faculty and students dating is right, but according to the website of Columbia university it doesn't apply to a relationship between Ted and her. Excerpt from the policy on consensual romantic and sexual relationships between Faculty and Students of Columbia University: "It is the policy of the University that no faculty member shall have a consensual romantic or sexual relationship with a student over whom he or she exercises academic or professional authority."
Correction: Ted actually points out to Cindy that because he is not her professor there's no real issue, but Cindy still shoots him down. Presumably it's because Cindy is actually attracted to women (which the audience won't find out until later), but can't actually admit it to herself and instead looks for excuses to sabotage her relationships with men.
Corrected entry: When the girls are in The Wedding dress shop, the bottle of champagne shifts from the table to the floor between shots.
Matchmaker - S1-E7
Corrected entry: When Ellen takes the clipboards, she first holds one in each hand, then the shot changes and both are in one hand.
Slapsgiving - S3-E9
Corrected entry: When future Ted is counting the times Marshall slapped Barney, the first one is shown as the one at the bar, but this was before Barney decided 5 for eternity. The one that counts as the first is the one he gets after they watch Robin Sparkles' Video.
Corrected entry: In this episode they call Barney's mom "Loretta", but in the 10th episode of the 3rd season, "The Yips", Rhonda "Man-Maker" French calls her Patty.
How I Met Everyone Else - S3-E5
Corrected entry: In this episode we get to see when Ted met Marshall. But in Season 2, episode 1 Ted says to Marshall, "And there was my roommate, lying on the bed with his feet up on the wall. He had headphones on, big smile on his face. That guy was you." In this episode we get to see it was different. (00:04:40)
Correction: I just watched this episode and you've taken it out of context. Ted had picked a time before Marshall had met Lily to show him that he can be happy without her and used walking in to see his confident, happy room mate as an example. At no point does he say that that was the first time they met.
Corrected entry: Barney's brother's child is now a girl. At his wedding in a previous season the child was a boy.
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.
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.