^ From the eighth season onward, episodes of each season initially aired on Monday nights, before later returning to the Thursday night slot for the rest of the season. The eighth and ninth seasons returned on the seventh episode, the tenth and eleventh seasons on the sixth episode, and the twelfth season on the second episode.
In 2010, Leonard, Howard, and Raj mined a lot of Bitcoin, now worth thousands of dollars, but left Sheldon out due to his fear of tax implications. Flashbacks are shown of how the Bitcoin ended up on an old laptop of Leonard's, which Penny gave to her old boyfriend Zack after she and Leonard broke up. In 2017, Leonard and Penny retrieve the computer from Zack, who first shows them a video of a drunken Penny apologizing for breaking up with Leonard. The Bitcoin is not found on the laptop. Sheldon had moved it to a flash drive on Leonard's keychain to teach the guys a lesson, but Leonard lost the keychain years ago. A final flashback to 2013 shows Stuart discovering the flash drive, which he decides to erase and sell for $10.
When Raj misses out on a job at the planetarium, his father says he has no confidence because Howard always makes fun of him. Raj distances himself from Howard and later gets the job. Howard is hurt by this (even after apologizing to him) and tries to make amends with Raj after his first performance at the planetarium but, when he sees him get a date, he leaves without speaking to him, thinking that the latter's life is better without him. Meanwhile, Sheldon and Amy try randomly dividing up wedding tasks, but they keep arguing. The only thing they can agree on is to get married, so they decide to just get married at City Hall. However, Sheldon decides that he wants a first dance with his new wife and they go home to plan their wedding.
"The Locomotive Manipulation" is the first episode in which Sheldon initiates a kiss with Amy. Although initially done in a fit of sarcasm, he discovers that he enjoys the feeling. Consequently, Sheldon slowly starts to open up over the rest of the season, and starts a more intimate relationship with Amy. However, in the season finale, Sheldon leaves temporarily to cope with several changes and Amy becomes distraught. However, in "The Prom Equivalency", he hides in his room to avoid going to a mock prom reenactment with her. In the resulting stand-off, Amy is about to confess that she loves Sheldon, but he surprises her by saying that he loves her too. This prompts Amy to have a panic attack.
Amy and Howard begin collaborating on a neuroprosthetics project, upsetting Sheldon and Raj, who feel they are not spending as much time with them. When they seek solace with an annoyed Bernadette, she exploits the situation to trick Sheldon into doing Howard's chores. Penny successfully employs the approaches recommended in one of Bernadette's parenting books to deal with Sheldon, but Leonard believes she is coddling Sheldon too much. Sheldon and Raj resolve the issue of missing their significant others by spending time together.
In the episode "The Launch Acceleration", Amy tries to use her "neurobiology bag of tricks" to increase the attraction between herself and Sheldon. In the final fifth-season episode "The Countdown Reflection", Sheldon takes Amy's hand as Howard is launched into space. In the sixth season first episode "The Date Night Variable", after a dinner in which Sheldon fails to live up to this expectation, Amy gives Sheldon an ultimatum that their relationship is over unless he tells her something from his heart. Amy accepts Sheldon's romantic speech even after learning that it is a line from the first Spider-Man movie. In "The Cooper/Kripke Inversion" Sheldon states that he has been working on his discomfort about physical contact and admits that "it's a possibility" that he could one day have sex with Amy. Amy is revealed to have similar feelings in "The Love Spell Potential". Sheldon explains that he never thought about intimacy with anyone before Amy.
Producers, writers and others, including recurring guest star Wil Wheaton, joined the festivities on set and — hardly a spoiler alert — more laughing, crying and hugging ensued. Lorre embraced a happy Parsons, then moved on to each cast member as if it were a reception line. Galecki shared long, emotional hugs with his colleagues. After trying to keep their emotions under control for so long, it was finally time to just let go.
The Big Bang Theory is an American comedy television series created and executively produced by Chuck Lorre and Bill Prady. Like the name of the series itself (with the exception of the first episode "Pilot"), episode titles of The Big Bang Theory always start with "The" and resemble the name of a scientific principle, theory or experiment, whimsically referencing a plot point or quirk in that episode.
Howard and Raj are still fighting, so Howard dis-invites Raj to Halley's birthday party. However, when Stuart pulls out as party planner at the last minute, Raj agrees to plan the party, which doesn't turn out too well due to Halley being asleep, Bernadette being on bed rest, and no people turning up. When Howard and Raj get into a shoving match in the party's bounce house, they end up letting out their frustrations, but also having fun and reconciling. Leonard is depressed upon receiving his successful brother's Christmas card and attempts to make a list of what he and Penny accomplished this year, not coming up with much. This prompts them to think about their plans for the future, so they decide to go on trips and achieve more out of life together before starting a family. Sheldon cooks Amy a Little House on the Prairie-themed birthday dinner, which gives them both food poisoning. They eventually recover enough to attend Halley's birthday party with the others, where they have fun in the bouncy castle and then have sex in Howard and Bernadette's house.
Two nerdy physicists share an apartment and an unlikely friendship with their beautiful neighbor with whom one of them is infatuated. Like the universe after the big bang, the show's popularity expanded, thanks to breakout star Jim Parsons, along with the chemistry among the friends and the developing romance between Leonard and Penny. The addition of Melissa Rauch and Mayim Bialik in later seasons also enhanced the stories and relationships of the leads.
Simon Helberg as Howard Wolowitz: An aerospace engineer who got his Masters at MIT. Howard is Jewish and lived with his mother, Debbie (Carol Ann Susi). Unlike Sheldon, Leonard, Raj, Bernadette and Amy, Howard does not hold a doctorate. He goes into space, training as an astronaut and serving as a payload specialist. Howard initially fancies himself as a womanizer, but he later starts dating Bernadette, and they get engaged and married. Howard also has a tendency to waste money on toys and argues with Bernadette because of his oddly low income as an engineer and her high income as a pharmaceutical biochemist.