She denies being Raj's girlfriend, and escapes after he becomes sick from overdrinking. Leonard and Penny quickly patch up their friendship. Meanwhile, Bernadette and Amy lament that they can't share their professional successes with their significant others, who are more than willing to toot their own horns. Sheldon eventually makes a research breakthrough he tells Ramona he would never have achieved without her, and gratefully asks how he can repay her. After some hesitation, he decides to go and wants Leonard, Howard and Raj to join him; they too initially hesitate as it would mean being locked in a cabin with Sheldon for three months, but finally agree. Penny's gift to Sheldon is a napkin both autographed and used by Leonard Nimoy. Sheldon worries about the approaching Christmas holidays and his indecision about what to buy for Penny, as he needs it to match the value of her gift to him.
Leonard then tries approaching her figure within the game, but she merely beheads his figure. Season 2 of The Big Bang Theory returned to television in September 22, 2008, and contained 23 episodes. So sex is just Leslie's way of controlling Howard. Leonard finally gets his chance, but Summer gets off the train before he can introduce himself. The next morning, Leonard suggests Penny should join Pasadena City College, but after she asks, says he does not mind dating someone who is not smart, at which she slams her door in his face. This pays off when Sheldon goes rock climbing with Kripke, but Sheldon faints due to his fear of heights. The show distinguishes itself by being unafraid to toss scientific references and technobabble into an otherwise standard sitcom, even employing a physicist to keep things accurate.
They try to determine who by playing the game but, yet again, all choose Spock. Penny is in financial difficulties and might even need to find a new place to live. Rounding out the crew are the smarmy Wolowitz, who thinks he's as sexy as he is brainy, and Koothrappali, who suffers from an inability to speak in the presence of a woman. At the comic book store, Stuart tells Leonard that he is having a second date with Penny and asks for advice. However, the next morning, they discover that the same group doubled their order, and the guys to quit in exhaustion.
To take his mind off the situation, Leonard asks Howard and Raj to take him to a bar to socialize with women, but neither he nor Howard succeed in finding a woman. Penny, initially unaware of Leonard's new relationship, shows up in the guys' apartment, and then searches Leonard's room with him, discovering various signs that Stephanie is indeed living with him. Things come to a halt when David meets Penny and the two start dating - though they quickly break up when Penny discovers nude photos of his wife on his phone. Howard's character remains similar to that of season one in his attempts to seduce women, while Rajesh manages to briefly communicate an apology to Penny without having consumed alcohol. With Sheldon's help, Penny develops an efficient assembly line, and Howard, Raj and Leonard later join in. Meanwhile, Sheldon sneaks into the hospital to test himself, as his tinnitus has not stopped. On the train, the guys notice Summer Glau of Terminator: The Sarah Connor Chronicles is on their car.
Despite their initial happiness, they realize Leonard included a one-day rush shipping option on the website, so the group has to work all night to fulfill the order. Raj becomes arrogant after receiving star treatment from Dr. After an unsuccessful attempt by Howard to rent the apartment, an attractive blonde named Alicia moves in. Sheldon, on the other hand, immediately develops a comfortable relationship with Beverly, who turns out to be as strict and logical as himself. Leonard later goes to talk to Penny and they comfort each other by discussing their respective childhood issues with their parents. However, she accidentally touches Sheldon's onion rings and sits on his spot on the couch, thus scoring 'three strikes' including an earlier 'offense', so he banishes her from his apartment.
Sheldon, still upset and dissatisfied with his eventually dry-cleaned cushion, team-kills Penny in the next paintball game, causing the others to surrender. Almost immediately, however, Sheldon deliberately provokes an argument with Leslie over the validity of loop quantum gravity, which Leslie supports, and string theory, which Sheldon favors. On arriving, Beverly meets Penny; by the time they have climbed the stairs to Leonard's apartment, Penny is in tears after being psychoanalyzed over her childhood issues with her father. Apart from Sheldon the guys are fascinated by Alicia, and she takes advantage of this by having them help her move in and otherwise labor for her. Penny tries to win her friends back by bribing them with Chinese food, offering to watch Battlestar Galactica with them, and even memorizing a quantum physics joke.
Leonard and Penny's relationship, which started with a date in the first season finale, ends quickly when Penny worrys she's not smart enough for Leonard. Penny's feelings for Leonard become clearer at the end of the season, as Leonard and the guys heads away for a three-month expedition in the Arctic. On the night before the expedition, Leonard expresses doubts on going as it will mean not seeing Penny for the whole summer. Stephanie gives him the necessary stitches at her hospital and later tells him she will not be sleeping with him that night as planned, as he needs rest. There Sheldon tries making friends with a little girl, but Leonard makes him exit quickly before he is picked up as a pedophile.
However, Sheldon dismays Leonard by joining the couple when they have a romantic dinner and go to the movies. Sheldon talks instead of sleeping, so Howard gives him Valium, which fails to work, and finally takes him back to the apartment. In the end, Penny is horrified to realize she has accepted a virtual date with Howard, and promptly stops playing, thus overcoming her addiction. The profile Leonard does give, however, in an unflattering one to the department, the university and physics in general. She later refuses to serve him at the Cheesecake Factory. Leonard becomes worried when he learns his mother, accomplished psychiatrist and neuroscientist Dr. Sheldon wins a National Science Foundation grant to go on a three-month expedition to the Magnetic North Pole to detect magnetic monopoles and prove the validity of string theory.
When, again, all choose Spock, they conclude that someone must stop playing Spock. For several days Leonard works on an experiment involving a free-electron laser which is only available at night, so he cannot drive Sheldon to the university as usual. Meanwhile, Leonard meets visiting researcher and fellow experimental physicist Dr. His parents object that she is not Indian, though his father likes Penny's resolute nature. However, Sheldon turns out to be an appalling driver, claiming to be 'Homo novus automobilis' and therefore too highly evolved to learn to drive, so he decides to live in his university office to avoid having to commute. The guys try to convince Leonard that the date went badly, which he denies.
After becoming drunk, Penny and Leonard end up in bed together, but Leonard ruins the moment by invoking psychiatric theory, implying that he is effectively having sex with his mom and she with her dad. The show was renewed for a further two seasons in March 2009. Howard then takes over, but creeps Summer out with his awkward style. After discussing this with her, Sheldon does the logical thing and lends her some money which she can repay at her leisure. A key moment in their friendship comes when Penny gave Sheldon a napkin signed by Leonard Nimoy for Christmas. The next day, Leonard feels guilty and goes to apologize to him. They, along with Howard, then play the game for Leonard's dumpling.