After being on the air for almost an entire decade, it was understandable that The Big Bang Theory was no longer at the peak of its historic run when season 9 came around.

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The show would still pull in Emmy nominations every year, but usually not any of the major categories. Despite the nerdy show being in decline, the fall was quite slow as the CBS comedy continued to produce hilarious sitcom content.

The Meemaw Materialization, Episode 14 (7.6)

Meemaw meets Sheldon and Amy on The Big Bang Theory

Audiences had heard of Sheldon's infamous Meemaw countless times throughout the series and they finally got the chance to meet her in this episode when she visited Pasadena to meet Amy. Sadly, the visit isn't very pleasant as Meemaw immediately informs Amy that she doesn't like her, nor does she approve of her dating Sheldon. When Amy finally confronts her and asks why, Meemaw states that it's because she hurt Sheldon deeply when she broke up with him at the end of season 8 (having since reconciled). Sheldon admits to his Meemaw that while he was hurt, he also knows that he and Amy help each other be better people - so Meemaw agrees not to stand in their way.

The Valentino Submergence, Episode 15 (7.6)

Howard and Bernadette with a rabbit at their house in Big Bang Theory

Normally in a sitcom that lasts over a decade, one or more of the main characters will usually have had a child (or expanded their family in some way or another). But other than a tiny dog for Raj, The Big Bang Theory main cast had yet to add any new family members to their group since season 3. That is, until this special Valentines Day episode where Sheldon and Amy do a 'Fun with Flags' episode, Leonard and Penny realize they're getting old, Raj has problems with his girlfriend...  and Bernadette reveals that she's pregnant with Howard's child.

The Application Deterioration, Episode 18 (7.6)

It's no secret that Sheldon had more than a few annoying (and controlling) traits that drove the rest of the group insane. However, this was a rare episode where somebody else in the group caused the problem simply because they thought Sheldon would be a problem. Sheldon, Leonard, and Howard want to patent one of their ideas and Sheldon draws up a contract for the three of them to sign that splits the profits an equal three ways. However, Bernadette begins trouble and insists that Howard should have somebody look it over before signing it because Sheldon is known for hiding loopholes that benefit him. Eventually, the two sit down and work out a contract that includes a few more things than just their patent.

The Convergence Convergence, Episode 24 (7.8)

The season 9 finale gave audiences quite a twist when Leonard and Penny decided to get re-married only one year after they tied the knot in Vegas so that their friends and family could attend the event. Guests included Leonard's mother, Sheldon's mother, and for the very first time audiences got to meet Leonard's father.

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Everybody goes out to dinner the night before the wedding and tension brews between the parents, culminating with Leonard's father and Sheldon's mother leaving together and sharing a cab to their hotel. The season ends on the cliffhanger of the possibility of Sheldon and Leonard becoming step-brothers.

The Bachelor Party Corrosion, Episode 3 (7.8)

Since Leonard and Penny decided to spontaneously get married in the first episode of the season, the guys decided just two episodes later that they should throw Leonard a late bachelor party. They rent a van that was owned by one of their favorite physicists and take a trip to Mexico to stay in a vacation home that also belonged to said physicist... except that they never reached Mexico since the van broke down on the side of the road and in the process of trying to fix the problem they ended up burning the van down. Good trip.

The Platonic Permutation, Episode 9 (7.9)

At the end of season 8 when Amy broke up with Sheldon, they made it clear that they still wanted to be friends, so since neither of them had any plans for Thanksgiving in this episode, the two of them decide to go to the aquarium together - as friends. They end up having a really nice time and Sheldon admits to Penny he's glad that he can still be Amy's friend - but then things get emotional when Amy tells Sheldon that she wants to be his girlfriend again, and Sheldon admits he can't do that since getting over her leaving him was too hard for him to possibly endure a second time.

The Spock Resonance, Episode 7 (8.0)

Season 9 sure pulled on the heartstrings. With the first half of the season focusing primarily on the aftermath of Sheldon and Amy's break-up, it was nice when they finally gave audiences a break where they got back to the nerdy stuff and had Sheldon get interviewed for a documentary about Leonard Nimoy (Spock).

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Alas, during the interview it somehow comes up that Sheldon has an engagement ring and was going to propose to Amy, and despite their break-up he decides to go see her and propose anyway... only to show up at her apartment and see her on a date with another man, causing him to turn around unnoticed.

The Mystery Date Observation, Episode 8 (8.0)

With Sheldon and Amy broken up, Amy was free to see other people and eventually landed a date with a fellow scientist named Dave. Due to jealousy from Amy moving on, Sheldon asks Howard and Raj to find him another girlfriend (since they found Amy) and the two construct an intricate series of puzzles that only Sheldon's soulmate could answer with the clues leading to apartment 4A. Meanwhile, Amy goes on her date and it seems nice... until Sheldon comes up and Dave reveals that he's an enormous fan of Sheldon's work and only wants to talk about him.

The Earworm Reverberation, Episode 10 (8.4)

So much Sheldon and Amy this season. In the episode following the Thanksgiving special where Sheldon informs Amy they have to just be friends, he finds that he can't get a certain tune out of his brain and it simply won't stop. After days of the tune still being stuck in his head, Sheldon begins to think he's going insane and descending into madness. However, he finally realizes that the tune is a song that reminds him of Amy - taking the hint he rushes off to Amy's apartment, interrupts her date, says he loves her and wants to be with her, and the two finally get back together. Dave was really cool about the whole thing too.

The Opening Night Excitation, Episode 11 (9.1)

Sheldon and Amy in bed together in TBBT

The episode directly following Sheldon and Amy getting back together made one of the biggest revelations in the entire series - Sheldon wanted to give his virginity to Amy as a birthday gift. Meanwhile, the rest of the guys were ecstatic due to the release of The Force Awakens and were trying to contain their excitement for opening night. However, their buddy Wil Wheaton points out that the movie could be absolutely terrible, and it genuinely wouldn't affect their lives at all. Simultaneously, Sheldon and Amy finally do the deed and it turns out that Sheldon Cooper is quite the lover. He then informs Amy that he looks forward to doing it again... on her next birthday.

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