Recaps for all the episodes in Season 3.

Episode 01: The Electric Can Opener Fluctuation
The guys get back from the North Pole and tell Sheldon they altered his research in an effort to put him in a better mood for the duration of the trip. Sheldon is humiliated because he already notified his colleagues at the university of his successful expedition. Devastated, he resigns from the university and runs back home to Texas and his mother (played by Laurie Metcalf). The guys go after him in an effort to convince him to come back with them.

Penny is so excited to see Leonard back from the trip that she immediately drags him into her apartment, kissing him incessantly. Both soon realize that being “friends with benefits” is not necessarily a natural fit for them.

Episode 02: The Jiminy Conjecture
Leonard admits to the guys that sex with Penny was not all it was cracked up to be. He tells them in confidence that it was just “fine.” While hanging out later as a group, Sheldon spills the beans, and poor Penny feels awful. Leonard tries to make up with her and they talk about why it is so weird between them. They decide they need to have a drink and loosen up a little bit. In the mean time, Sheldon and Howard make a bet regarding the type of cricket they hear chirping in the building. Once they find the cricket in question, they take it to the university etymologist played by Louis Black. Howard wins the bet and takes possession of one of Sheldon’s prize comic books. Penny and Leonard get a little too loose, and both end up getting sick, leaving their new intimate relationship in an even weirder place.

Episode 03: The Gothowitz Deviation
Wolowitz meets a Goth girl online. When she asks to meet at a local Goth club, Wolowitz takes on his own Goth persona in order to impress the girl. Wolowitz and Koothrappali go to the club to meet her and her friend. The girl seems into Wolowitz and suggests they go get tattoos together. Wolowitz, thinking he is going to score, agrees to go. But all goes bust when Wolowitz chickens out of getting a real tattoo.

Sheldon is trying to use positive reinforcement to train Penny to behave how he likes. Leonard catches on and initially is appalled by it, telling Sheldon to stop. But when Leonard sees how well it works, he decides to use it on Penny to achieve his own objectives. Penny catches on and gives Leonard a little negative reinforcement.

Episode 04: The Pirate Solution
Koothrappali reveals to the guys that he will soon be deported since the university will no longer fund his research and he is here on a work visa. Wolowitz, devastated by the news, tries to find Koothrappali a new job. Koothrappali ‘s interview is initally going well until he is introduced to his new team member, a beautiful female scientist. He then takes a couple of shots of sherry to loosen himself up and ends up hitting on the beutiful scientist and blowing the interview. Sheldon comes up with the idea that Koothrappali can come work for him. At first, Koothrappali prefers deportation but soon reconsiders. When Koothrappali begins to question Sheldon’s research methods, Sheldon fires him just as Koothrappali quits.

Episode 05: The Creepy Candy Coating Corollary
Koothrappali wants Sheldon to be his partner in a card tournament because Sheldon can count cards. Koothrappali hears that Wil Wheaton will be in tournament and is very excited while Sheldon is not. He tells Koothrappali a sad story of how when he was young he made his way a long distance to meet Wil Wheaton and Wil did not show up to the event which devastated Sheldon and made him forever hate Wil Wheaton. Sheldon meets up with Wil Wheaton in the finals. Wil is not understanding why Sheldon hates him and Sheldon finally tells him his sad story. Wil tells Sheldon that was the year his grandmother died and Sheldon has sympathy for this and begins to tell Wil how he understands and how much he loves his “Mee Maw” too. Sheldon begins to feel bad for Wil and ends up throwing the match and letting Wil win only to find out Will made up the whole grandmother story.

Wolowitz reminds Leonard of a pact they once made that if any of them every managed to get a hot girlfriend they need to have the hot girlfriend hook up the guys with her hot friends. Penny who reluctantly agrees and they are going to have a double date. The date is going horrible until the girl makes a comment of how awful her mother is. They start to tell “mommy dearest” stories and find themselves bonding over their mutual hatred for their mothers.

Episode 06: The Cornhusker Vortex
Penny is having a football watching party and initially does not invite Leonard. Leonard thinks its less about his lack of football knowledge and more about Penny being embarrased to introduce him to her friends. Penny reassures Leonard that is not the case and invites him to watch next week’s game with her friends. We find out that Sheldon is a football savant and knows everything about the game. Leonard enlists his help and asks Sheldon to come to the party to feed him football facts in order to impress Penny and her friends. It back fires on Leonard when Sheldon takes over as the hit of the party.

Episode 07: The Guitarist Amplification
Penny and Leonard have a huge fight after Penny tells him that a male musician friend of hers, who she dated for a short time, is coming to stay with her while he is in town. Leonard is enormously bothered by this and can’t understand why Penny thinks it is fine. They begin to argue and we find out that Sheldon cannot take hearing people argue. Apparently Sheldon heard his parents argue all the time and it traumatized him. Koothrappali and Wolowitz then take sides and begin to argue about who is right in the fight between Penny and Leonard. Sheldon can’t handle anymore fighting so he takes refuge in the comic book store where Penny and Leonard have to convince him that they are done fighting in order to get Sheldon to come home.

Episode 08: The Adhesive Duck Deficiency
Leonard, Koothrappali and Wolowitz head to the desert to see the Leonids meteor shower. While camping, Wolowitz starts hitting on a few girls, gets nowhere but they give him some cookies to get him away. The guys eat the cookies and soon realize they received an extra ingredient they didn’t expect. The guys sit around the campfire, high off their cookies, when Wolowitz reveals how he lost his virginity to his second cousin. Initially this doesn’t register with Leonard and Koothrappali in their altered state but this information is not soon forgotten by either. The guys get the munchies and in their feeding frenzy, forget all about the meteor shower.

Penny falls in the shower and Sheldon comes to her aide. The awkwardness of finding her naked is not lost on either but Penny is really hurt and Sheldon must now drive her to the hospital. As Sheldon goes through his pre-driving ritual, Penny tries to keep her cool but he finally manages to get her to the hospital. After the hospital, Sheldon takes her back to her apartment and Penny requests that he now sing her “Soft Kitty”. Penny tells Sheldon how much she cares for him and how happy they are friends. He is visibly uncomfortable but appreciates what she is saying.

Episode 09: The Vengeance Formulation
Wolowitz gets nervous about committing to Bernadette and begins to pull away from her. When he realizes he has made a mistake, he goes overboard and proposes to her. She is shocked by this over the top gesture. Wolowitz realizes he went overboard and apologizes; Bernadette accepts. Wolowitz decides a verbal apology is not sufficient and procedes to sit down at a piano and sing Bernadette an apology to tune of the Four Tops song “Bernadette”. While Penny is horrified, Bernadette thinks it is sweet since no one has ever sung to her before.

Kripke plays a prank on Sheldon during his interview with Ira Flatow. Sheldon vows revenge and devises the ultimate prank to get back at Kripke. The prank works, but unfortunately for Sheldon, the President of the university and the board members are caught in the mix.

Episode 10: The Gorilla Experiment
Penny feels left out of all the science talk now that Bernadette is part of the gang. She enlists Sheldon to teach her about physics. In the mean time, Wolowitz gets irrationally jealous when Bernadette shows interest in Leonard’s work. Wolowitz lets Leonard know that he better stay away from his “girlfriend.” When Bernadette gets wind of Howard’s jealousy, she threatens to break up with him. He apologizes and realizes there is no harm done. Back at Sheldon and Leonard’s apartment Penny struggles to learn the basics of physics form Sheldon. Penny surprises everyone at the end of the episode when she rattles off a monologue about what Leonard is working on.

Episode 11: The Maternal Congruence
Leonard’s mother, Beverly (Christine Baranski), returns for a visit and Leonard is less than excited. Penny finds out that Leonard hasn’t told Beverly they are in a relationship and she tries to find the right moment to give Beverly the news. Beverly informs Leonard that she and Leonard’s father are getting a divorce after she discovered he cheated on her but Beverly seems un-phased by the situation. Penny gets Beverly to open up after stopping at a bar where they bond over shots of tequila. Penny finally tells Beverly about her and Leonard’s relationship and she seems to take it well in her own over-analytical way. In her drunken haze, she plants a huge kiss on Sheldon but realizes she would prefer the busboy at the bar. Beverly and Leonard come to a new understanding about how they need to include one another in their lives more and Penny is thrilled that Beverly, even after naming off a list of Penny’s shortcomings, thinks she is adorable.

Episode 12: The Psychic Vortex
Penny and Leonard get into a big blow up over the fact that Penny visited a psychic and actually believes what the psychic told her. Leonard ends up apologizing and actually agrees to meet Penny’s psychic. Bernadette and Wolowitz continue to date and are getting along swimmingly. In the mean time, Raj is feeling really left out, because he is the only one without a girlfriend. He bribes Sheldon to go to a mixer with him down at the University where they meet two really cute girls and one of the girls really likes Sheldon. They all go back to Sheldon and Leonard’s apartment, and as Raj gets cozy with one of the girls, the other girl, Martha, suggests to Sheldon that she “tuck him in.” This goes right over Sheldon’s head and he totally rejects her advances and just replies, “Oh thanks, but the only person who tucks me in is my mother.”

Episode 13: The Bozeman Reaction
Sheldon and Leonard’s apartment is broken into and Sheldon decides to install a home security system that goes all wrong and ends up ensnaring Penny in a net. Sheldon is so nervous about another break in, he won’t leave Penny and Leonard alone, and insists on sleeping in their room with them. In the end, he decides to move to Bozeman, the safest city in the country. Unfortunately, when he arrives, he is immediately robbed at the train station, so he buys a one-way ticket back to Pasadena.

Episode 14: The Einstein Approximation
Sheldon is suffering from “Theorist’s block” and cannot complete a formula he has been working on for sometime. Taking inspiration from Einstein, who discovered the theory of special relativity while working in a patent office, Sheldon takes a menial job busing tables at the local Cheesecake factory in an attempt to jump start his brilliance. He was never actually hired at the Cheesecake Factory but decides to just to start working in an effort to clear his block. Penny tries to stop him but Sheldon is doing surprisingly well and even serves the guys’ a meal. Sheldon finally achieves the great breakthrough he is looking for- it comes in the form of a broken dish.

Episode 15: The Large Hadron Collision
Leonard is invited to Switzerland on Valentine’s Day to see the CERN Supercollider, the world’s largest and highest-energy particle accelerator, and Sheldon is shocked when Leonard decides to take Penny, making it a romantic Valentine’s Day present, instead of him. Sheldon tries several angles in an effort to change Leonard’s mind including guilting Penny into not going, but Leonard isn’t budging and tells Sheldon that he would rather go alone than take him. Unfortunately for Leonard, Penny gets sick the night before they have to leave so Leonard decides to make peace and invite Sheldon to go. When Leonard gets to the apartment, he finds Sheldon is horribly sick too. Penny and Sheldon end up staying home sick together and Leonard is forced to take Koothrappali to Switzerland for what was supposed to be a romantic getaway.

Episode 16: The Excelsior Acquisition
Sheldon is summoned to traffic court after getting a ticket for running a red light while taking Penny to the hospital (episode #308) and misses meeting Stan Lee, creator of Spiderman, at the comic book store. While in court Sheldon insults the judge and ends up in jail for contempt. He threatens to never forgive Penny for ruining his one and only opportunity to meet the great Stan Lee. Penny feels horrible and goes to the comic book store to ask Stuart for Stan Lee’s phone number. Stuart is so smitten with Penny, that he actually gives her Stan Lee’s home address. Penny takes Sheldon to Stan Lee’s house but Stan Lee has Sheldon arrested…again.

Episode 17: The Precious Fragmentation
In a parody of “The Lord of the Rings,” the guys fight over a ring they believe was an original prop from the movie. Leonard wants to give the ring back to its original owner. Koothrappali wants to sell it so that he can get a jet ski. Sheldon wants to keep it so badly that he actually starts to turn into Gollum from the Lord Of The Rings movies. Sheldon sneaks into Penny and Leonard’s room in the middle of the night to steal the ring off of Penny’s neck where she is wearing it to keep it safe, and Penny punches him in the nose. In the end Leonard sends the ring back to New Zealand to the original owner. However, in the tag we see that Leonard has lied about sending it back to New Zealand, and has really hidden it in his room.

Episode 18: The Pants Alternative
Sheldon finds out he is being honored with a prestigious award by the University and suddenly gets stage freight and wants to decline the award just so he won’t have to stand in front of his colleagues and give a speech. Penny wants to help Sheldon regain his confidence and enlists the guys to help her do it. She convinces Sheldon to allow them to help by comparing them to the “X-Men” team, which Sheldon gets in to and calls his team the “C-Men,” which the guys hate. Penny takes Sheldon to buy a professional suit, while Leonard and Koothrappali try to provide psychological and spiritual guidance without much success. On the night of the event, Sheldon initially appears composed but soon his nerves get the best of him and as he is about to be introduced to the stage, he wants to run out. Penny gives him the only thing she knows will calm him down and get him through this speech – alcohol, and lots of it.

Episode 19: The Wheaton Recurrence
Leonard tells Penny he loves her but she replies with “thank you” which was not the response that Leonard was looking for. Leonard is hurt and Penny feels him pulling away and explains to him that she has said “I love you” too early in a relationship and the outcome wasn’t good so she didn’t want to rush into it and ruin what they have.

Sheldon, Penny and the guys meet up with Stuart’s team at the bowling alley but Stuart has a surprise replacement for a regular teammate – Wil Wheaton. Sheldon thinks this is his moment to take his revenge but Penny and Leonard get into a fight while bowling and both storm off making Sheldon forfeit the game to Wil’s delight. Sheldon facilitates Leonard and Penny’s reconciliation solely for the reason that he needs both to play a rematch game with Wil Wheaton and his team. The game is pretty close and Wil hones in on Penny’s insecurities about saying “I love you” to Leonard, essentially playing mind games, in order to throw off her game. His tactic works and Penny runs off yelling at Leonard and Sheldon must forfeit to Wil once again. But Sheldon vows he will get his revenge.

Episode 20: The Spaghetti Catalyst
Sheldon tries to hide from Leonard that he is still “seeing” Penny. When Penny runs into Sheldon in the hallway and he expresses to her that he would like to remain friends, even though she and Leonard are no longer “coitusing,” Penny is pleasantly surprised at Sheldon’s overture, and invites him to dinner. Sheldon then feels compelled to hide his continued friendship with Penny form Leonard. In doing so, he eats dinner and home with the guys, and then pretends he is going for a walk and sneaks over to Penny’s for another dinner. Finally the lying breaks him down, and he tells Leonard that he is still “seeing” Penny. Leonard does not mind. Penny and Leonard embark on a divorced-parent-like relationship with Sheldon. At the end of the episode, they agree that they can be friends.

Episode 21: The Plimpton Situation
When Sheldon meets a famous female physicist online, and invites her to come visit and stay at his apartment, Leonard quickly realizes that it is the famous and very attractive female physicist that he has a big thing for. It turns out that she is interested in Leonard, and pays him a visit to his room in the middle of the night. The next day penny gets wind of this, and criticizes Leonard for jumping into bed with someone else so quickly. And Sheldon feels betrayed because Leonard is “playing with HIS friend.”  It turned out that this woman played by Judy Greer is a bit of a hussy, and comes on to all the guys, culminating in a hilarious scene where she proposes a foursome. The boys back out.

Episode 22: The Staircase Implementation
In this episode we trace the history of Sheldon and Leonard and the guys. Penny asks Leonard why he ever moved in with Sheldon, and through flashbacks we learn the whole genesis of their friendship. It started 7 years ago when Leonard was simply looking for a roommate. Sheldon had advertised at the University, and Leonard went to the apartment to meet him. Upon arriving there, he met the old roommate, who told him to “run for you life!” In the apartment Leonard saw that the old roommate has scrawled “Die Sheldon, Die” on the walls. This is where we learn about the roommate agreement, and how Howard and Raj came into the fold. In the end, we find out that Sheldon actually saved all of their lives, by putting an experiment that Leonard was doing in the elevator, and shutting the doors, thereby making sure that Leonard was not near the explosion.

Episode 23: The Lunar Excitation
Raj and Howard sign Sheldon up for online dating, and find the perfect woman for him. She is the female version of Sheldon (played by Mayim Bialik). Penny shows up at Leonard’s door, drunk and lonely, and takes him straight into the bedroom. Leonard wakes up the next morning overjoyed until he finds out that Penny regrets the drunken encounter. Leonard decided he is going to try the same approach, and goes to the home of Leslie Winkle, (played by Sarah Gilbert). he attempts to have casual sex with her, and she shuts the door in his face.