Mayim Bialik as Amy Farrah Fowler (guest star season 3, starring seasons 4–12): A woman selected by an online dating site as Sheldon's perfect mate. Amy is from Glendale, CA. While she and Sheldon initially share social cluelessness, after befriending Penny and Bernadette she eventually becomes more interested in social and romantic interaction. Her relationship with Sheldon slowly progresses to the point at which Sheldon considers her his girlfriend, eventually they get married. Amy believes she and Penny are best friends, a sentiment that Penny does not initially share. Amy has a Ph.D. in neurobiology.
Kunal Nayyar as Rajesh Koothrappali: A particle astrophysicist originally from New Delhi, India. Raj is initially unable to talk to women unless he drinks alcohol. Raj also has very feminine tastes and often takes on a stereotypical female role in his friendship with Howard as well as in the group of four men. Raj later dates Lucy (Kate Micucci), who also suffers from social anxiety, but it eventually ends; he later speaks to Penny without alcohol and thus overcomes his selective mutism. He begins dating Emily and their relationship later becomes exclusive. Raj also has a Yorkshire Terrier named Cinnamon.
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.
I had never heard of Jim Parsons until I watched BBT but, his performance as Sheldon Cooper should be recognized as one of the greatest in TV history and the individual responsible for casting him should be considered a genius. Jim was born to play Sheldon. No other actor could’ve owned this character the way he did. I hope he continues to share his talent with audiences in other ways!
With all due respect to all of the Sheldon’s out there who can cite episode titles, describing the episode is a LOT more helpful that calling it out by name. I can quote my favorite line/scene from your post (Are they bouncing more than usual,) but “Mike’s” post above is a lot less memory provoking. What was “The Donation Oscillation” about? I can extrapolate MOST of the episodes from the title, but not all. Kudos to those with memories like Sheldon’s, but my bet is far fewer fans can describe an episode by season and title than they can by “The one where James Earl Jones and Sheldon ding dong ditch Carrie Fisher.” :)
Barry Kripke says that he can get proof that Pemberton plagiarized his thesis, which would destroy his chances at the Nobel Prize. Sheldon and Amy decide not to pursue this; they want to win on their own merits. Leonard decides to get the information from Kripke. Amy and Sheldon give it to Pemberton and Campbell, as they refuse to blackmail them. Campbell is furious that Pemberton's dishonesty could hurt his own career. It is revealed that Campbell is sleeping with Pemberton's ex-wife, causing the pair to brawl. Afterwards, Campbell exposes Pemberton, causing Pemberton to be fired. Amy and Sheldon reject a drunken Campbell's request to join their team. Bernadette tells Howard that another waitress at the Cheesecake Factory was attracted to him back in the day, so she said Howard had hepatitis to scare her off. Howard obsesses over who it was, until he tells Bernadette she is the only one that matters to him.
According to Steve Holland who is the show-runner starting with this season, Wil Wheaton will return in this season since his absence from Season 10. And this has confirmed to be true since it has been stated that he reappeared in "The Proton Regeneration" (S11E6), along with Professor Proton, their first appearances since "The Opening Night Excitation" (S9E11) and "The Celebration Experimentation", respectively and a span of 43 episodes and a span of 37 episodes, respectively. Wil also returned in the 15th episode. Wil will also return for Sheldon and Amy's Wedding.
After Sheldon reminds the guys about the time they mined Bitcoin without him, the guys go on a quest to find their suddenly valuable missing cryptocurrency. They realize the currency is on a laptop which Leonard gave to Penny when they dating, which she then gave to her ex-boyfriend Zack. After Leonard and Penny go to Zack's apartment, he shows them a seven-year-old video that Penny recorded on the laptop soon after she broke up with Leonard. Leonard is touched by the video which shows a drunk Penny lamenting the break-up of her relationship with him.