The Toast Derivation

"The Toast Derivation" is the seventeenth episode of the fourth season of the  sitcom The Big Bang Theory. This episode first aired on February 24, 2011.

Summary
Sheldon realizes he is not the center of his group, thus he attempts to form a different social group where he can be the center. Meanwhile, Penny tries to get over Leonard who just got into a new relationship with Priya.

Extended plot
Leonard is going over to Raj's apartment for dinner with the gang, Sheldon insists he stays because of their Thursday tradition of eating at their apartment. Leonard is still going so Sheldon tags along. After a brief unsatisfactory experience at Raj's, Sheldon heads to The Cheesecake Factory's bar alone and tries to get Penny to empathize with him. Amy video calls him and points out that Leonard is the "" of their social group.

Later, back at apartment 4A, Sheldon prepares some snacks for his forthcoming guests Stuart (who came to take a hot because he's living in his comic book store), Kripke (who came for a ), Zack (who isn't sure what he is or why he's there), and LeVar Burton (whom he invited via ); he does this to form a new social group where he is the "nucleus". At Sheldon's event, he announces that it seems LeVar Burton will not be attending, and kicks off the gathering with some introductory activities, in which all of the guests receive a containing a free copy of the fictitious The  Journal of .

Amy and Bernadette come over to Penny's to "kidnap" her for night out dancing to get over Leonard; she agrees if the two agree not to pester her about Leonard any further. They try to get Penny to go to a place where she can get a young guy to have sex with. She refuses, but then Amy and Bernadette point out the preserved from the  which Leonard gave her (in "The Electric Can Opener Fluctuation"). She then changes her mind.

Back at Sheldon's event, Zack impresses the gang (except Sheldon) with his racy story. Next, Sheldon asks the gang to choose between an array of vintage video games (', ' and Zork, which Sheldon emphasizes over the others by exclaiming, "Pick me! Pick me!") which the others find boring so Kripke decides to bring up his instead.

Back at Raj's, the gang is reminiscing about their experiences with Sheldon. Sheldon is suddenly at the door and he is greeted with a warm welcome.

In the final scene, in the apartment building outside apartment 4A, LeVar Burton ends up making an appearance to join them, but swiftly changes his mind after seeing Stuart, Kripke, and Zack singing "", with Stuart in a towel. And says he is so fed up with Twitter (with which Sheldon had invited him to the party).

Critics
"There was a lot to like about this episode. The producers seem to have embraced the idea that the show needs more characters and the results have been solid. Although there wasn't much depth we managed to explore Penny's feelings for Leonard, Leonard's relationship with Priya, and Sheldon's attitude to friendship all in one go... None of the three stories exactly took off but they were all adequate. The writers still try a little too hard with Amy." The TV Critic's Review

Quotes
Howard: Hey, Raj, did you ever tell your sister about the time Sheldon got punched by ?

Priya: Oh God, you're kidding!

Raj: (laughing) No. Gates gave a speech at the university. Sheldon went up to him afterwards and said "Maybe if you weren't so distracted by sick children in Africa you could have put a little more thought into ."

Leonard: Bam! Right in the nose! Made me proud to own a.

Sheldon: Well, no, sir, and do you know why? In a word, tradition. Every Thursday night for the last eight years, you and I and our friends have gathered here in this very spot to break bread covered with cheese and sauce, discuss the issues of the day, and yes, share a laugh or two. But I guess our rich heritage means nothing to you.

Howard: I think it’s like Beetlejuice. We said his name too many times.

Trivia

 * Raj's flat=screen HD has 2% dead  in the upper left corner.
 * Kripke is fond of s.
 * Priya ponders Sheldon buying a and weaving, while Leonard and Raj mention their s that Sheldon made; this is a reference to "The Luminous Fish Effect". Also, Priya talks about Sheldon adopting 25 cats, which occurred in "The Zazzy Substitution".
 * Sheldon once got punched by after telling him that maybe if he weren't so distracted by sick children in, he could have put a little more thought into .
 * Sheldon hates  and .
 * The preserved snowflake from the North Pole that Leonard gave Penny in "The Electric Can Opener Fluctuation" (S3E1) appears in this episode again.
 * Amy has an  which she calls "Gerard" used for.
 * When Sheldon goes to Raj's apartment and knocks, he says, "all my friends" 3 times between knocks.
 * Amy listens to "I'm Walking on Sunshine" while Sheldon takes care of her in "The Fish Guts Displacement".