Question: Whenever the gang always have dinner together why is it always in Leonard and Sheldon's apartment?
Chosen answer: Out of everyone's apartments, the gang likely eats and hangs out at Leonard and Sheldon's apartment because it has the largest living room space and they would be given the most amount of room to interact in. Raj's apartment and Penny's apartment do not appear to have as much living room space as Leonard and Sheldon's apartment, so they may not want to hang out there, nor would they want to hang out at Howard's place since his mother would be there.
In addition to this, I'm sure that Sheldon has some sort of rule that if they aren't eating at a restaurant, they eat at Sheldon and Leonard's place because it's where Sheldon is most comfortable.
In addition, I think a big part of the reason would be that 3 of the 5 (at first) friends lived in the same building so eating there meant fewer people had to travel. Plus, it was very quickly traditional for Penny to come over to Leonard and Sheldon's apartment to eat so it was natural it stayed that way. And lastly, it's not at Penny's apartment since Penny usually doesn't have money to pay for the food so since Leonard usually brings the food, it's logical everyone goes to his apartment.
This isn't true. In one episode, I can't remember which, the group eats at Raj's place with Priya. Sheldon expresses his displeasure to Amy who explains that Leonard is the nucleus and that where Leonard goes, everyone goes. Sheldon has no such rule about eating there.
Since he states his displeasure it proves he is more comfortable eating at home. He even doesn't like eating at a dinner table in his own apartment, let alone somewhere else entirely. He only compromises if he has no choice.
Question: Was it ever established how long Howard spent on the International Space Station? I ask because some story arcs that begin with one season's finale pick up immediately where the last season left off (S4-S5), but others take place more or less in real time, such as when the guys went on a scientific expedition to the Arctic Circle. So did Howard actually spend three months on the ISS, or was there a "time jump"?
Chosen answer: Howard went up on Expedition 31 and came back on 32. If the BBT universe holds to the same schedule as the real one, he would have been up there for approximately two months.
The Classified Materials Turbulence - S2-E22
Question: The piece of plastic Howard tells Raj is put in pizza boxes to keep the lid from touching the cheese—is there an actual name for it?
Answer: It typically goes by the name "pizza saver", but it's often called a pizza stool or pizza table (some have 3 legs and some have 4). When Carmela Vitale was issued a patent, she called it a package saver.
Question: What game are Amy and Sheldon playing in the opening scene? It's an app on a phone.
Answer: Heads Up, developed by Ellen DeGeneres. I believe it originally began on her talk show with the use of index cards.
The Viewing Party Combustion - S9-E21
Question: How come out of nowhere Leonard decides to not go to the roommate agreement meeting? I know he wouldn't want to but why just decide not to after about 13 years of these?
Answer: He was probably sick of it by that point. He has complained many times about roommate agreement regulations.
The Tangible Affection Proof - S6-E16
Question: Why did they get rid of Alex after this episode?
Answer: Plot-wise, there was no reason given for her exit. She was a minor character, not a regular, and writers often write them out of a series without an explanation. The actress, Margo Harshman, did go on to work in a web series the next season and, following that, had a more substantial role on NCIS.
The Decoupling Fluctuation - S6-E2
Question: Why does Bernadette seem surprised to hear that Amy can see her and Sheldon eventually getting married?
Answer: Bernadette is surprised at the thought that Sheldon could get married. Going against everything she knows.
The Escape Hatch Identification - S10-E18
Question: Raj makes a fair amount at the university so how come after his father stops supporting him for 2-3 weeks, he gets evicted?
Question: I don't get why Bernadette got mad at Howard just because he didn't tell her about a couple of women he used to date. I don't also get why she started getting upset and running to her room just because of what Penny said. Can someone please explain them to me?
Chosen answer: She is upset at Howard not because he didn't tell her, but because he lied to her. He claimed to have told her about all the women he slept with but didn't mention many of them. She is mad at Penny because she thinks Penny betrayed her by setting her up with someone she didn't respect and expected them to fail.
The Vacation Solution - S5-E16
Question: Why did Penny lie to Leonard by saying Bernadette wants a prenup when it's her dad who wants a prenup, and why is she gossiping about it in the first place?
Chosen answer: She is simplifying the situation. Bernadette may not be the one insisting on the Pren, but she is going to ask Howard to sign one. She's gossiping because she likes to gossip.
The Engagement Reaction - S4-E23
Question: When they're at the hospital Howard never said that he told his mother that he was engaged, so how would Bernadette know he said that?
The Prestidigitation Approximation - S4-E18
Question: Why is Penny looking so happy when she sees Leonard and Priya in the restaurant and going into the restaurant and looking like she doesn't plan to leave and eats their food? Wouldn't Penny of all people know not to disturb someone during a date?
Chosen answer: She's having a Leonard moment and not fully grasping the situation. She doesn't see her ex boyfriend and his new girlfriend having a romantic dinner, but two of her friends having a meal. Whether it was conscious or unconsciously is anyone's guess.
The Luminous Fish Effect - S1-E4
Question: Did the gang meet Mary before this episode? Because Leonard knew to call her but it seems like none of them ever met her before.
Chosen answer: It's unlikely that they ever met, which would mean Mary visited. However, the show seems to imply Leonard has had to call her in the past to help out with Sheldon, and he has her number. Plus, Mary seems to be more motherly (then say Beverly) and one can assume she's called Sheldon a number of times to check in on him and it's likely Leonard answered the phone some of those times and spoke to her. Given that Leonard often shares personal stories with the gang, it's also likely he's told the gang something about Mary.
Chosen answer: Probably because part of being in a relationship with someone means sharing their interests, even if you yourself are indifferent, to grow closer together. Penny feels otherwise.