The Friendship Algorithm Season 2, Episode 13 -  Aired January 19, 2009

The Friendship Algorithm

Sheldon wants to use the university's grid computer for his research, but access to the computer is controlled by Barry Kripke who apparently favors his friends. Sheldon decides to befriend Kripke, but struggles from a lack of experience in making friends. Treating this like any other scientific inquiry, Sheldon studies up and develops a friendship algorithm.

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Guest Stars: John Ross Bowie as Barry Kripke, Will Deutsch as Jeremy, Jane Galloway Heitz as Mildred, Jade Zdanow as Rebecca

Writers: Bill Prady (Story), Richard Rosenstock (Story), Chuck Lorre (Teleplay), Steven Molaro (Teleplay)

Director: Mark Cendrowski

Viewers: 11 million Households Rating: 5.4/9 Adults 18-49 Rating: 4/10

Available on iTunes

Episode Notes

  • The title references Sheldon's algorithm for making friends.

> Sheldon's Knock

Sheldon uses his knock when he goes to Penny's apartment to hand her a friendship questionnaire.

Episode Quotes

Sheldon: A fear of heights is illogical. A fear of falling, on the other hand, is prudent and evolutionary.

Wolowitz: *After he fixed Sheldon's algorithm* Gee, why can't Sheldon get a friend?

Sheldon: What part of an inverse tangent approaching an asymptote don't you understand?

Sheldon: "Barney Bunny has two daddies now." Probably something about homosexual rabbits.

Penny: What about Howard and Raj? How did he become friends with them?
Leonard: I dunno. How do carbon atoms form a benzene ring? Proximity and valence electrons.
Penny: Sure, when you put it like that.


Sheldon needs time on the university's open science grid computer and learns that Barry Kripke controls access and gives his friends preferential treatment. Sheldon sets out to befriend Barry so he can use the grid computer. After Sheldon's calls to Kripke fail, he decides to learn more about friendship making and fine tune his process.

Sheldon goes to a book store to try find a guide to making friends. He finds "Stu the Cockatoo is New at the Zoo" in the children's section, where he starts talking to a young girl. Leonard pulls him away from the store before he gets into trouble. The guys arrive at the apartment and find Sheldon has finished his "Friendship Algorithm" based on the book. Sheldon calls Kripke and attempts to find a suitable interest of Kripke's that they can share, but when Sheldon gets stuck in a loop, Howard must add a loop counter and an exit to the Least Objectionable Activity.

After Sheldon and Kripke decide they will go rock climbing together, Sheldon studies up on rock climbing - on the Internet of course. While climbing with Kripke, Sheldon realizes he has a fear of falling and seizes up, just "hanging there like a big salami". Back at the apartment, Kripke joins the gang for dinner. When Sheldon changes the subject to the grid computer, Kripke explains he has no control over the access list. With no further use for his friendship, Sheldon kicks Kripke out of his friendship circle.