Bernadette asks what about her and howard, and amy says they can come too, but looks at penny and tells her bernadette is feeling insecure.
Sheldon says then it is plausible, but then asks leonard again if he bought something.
Leonard's friends recalled on many occasions that they were together for only 27 days, after which joyce, later revealed to be a spy, defected to north korea.
When penny arrives at the apartment, howard begins to flirt with her but pushes it too far, and she furiously lashes out at him with some uncomfortable home truths.
Nevertheless, leonard often finds himself explaining sheldon's behavior or serving as a mediator between him and other people in many situations.
While certainly a geek by most definitions, he is less socially inept than sheldon (who is unable to grasp social norms and is often even dismissive of them), raj (who was unable to talk to women unless he was under the influence of alcohol or anti-anxiety prescription drugs, and even after getting over his handicap still tended to speak inappropriately), and howard (who was often seen as "creepy" when flirting with women, including penny).
Are sheldon and leonard named after the brilliant (producer) sheldon leonard of "the andy griffith show", "the danny thomas show", "the dick van dyke show", "my favorite martian" and "i spy?
Leonard says that is not true and sheldon agrees by saying leonard is wrong more than anyone he knows.
After deciding on a basket of bath items he discovers a large selection, so not knowing what penny will get him, he buys the entire range to cover all contingencies.
When does leonard and penny start dating again
Sheldon, overwhelmed since he now possesses nimoy's dna and can grow his own leonard nimoy, gives penny all the gift baskets and also a rare "sheldon" hug.
Leonard yells that he does not need to stand there and take this treatment and walks towards her apartment.
In addition, the characters are wearing similar items of clothing; penny, in fact, is wearing the exact same top in this scene that she wore in the pilot.
Later, leonard asks penny what exactly they are doing since every relationship scenario he plays out ends badly.
The season 4 finale, leonard runs into penny and raj as they come out of his room in the morning, just after leonard and priya appear to break up upon leonard's learning that priya is soon moving back to india.
Penny tells him it was fun and he agrees, except when he got the foot cramp.
Penny asks him how he would say it so leonard uses the words "have feelings" instead.
Reference: sheldon shows he is very willing to help his friends financially when he offers to help penny.
Leonard says that if anyone displeases him, he will not help them set up their printer.
When do leonard and penny start dating
As she has grown out of one-night stands she suggests they take it slowly, first determining their compatibility on all levels before proceeding to full sex (if at all); leonard can assume the "male role".
 leonard is embarrassed by his middle name and its humorous connotations, and rarely mentions it, as the name is an obvious embarrassment.
Reference: sheldon hanging penny's laundry from a wire and taunting her to play panty piata.
She then pulls his hand towards her apartment, when leonard starts talking and she tells him to be quiet, no talking.
Howard tells penny about all his failed romances, and she consoles him by saying that he is a good guy at heart and he just tries too hard to get girls.
Sheldon does not understand the laughter and tells them that the objective of the game is to build roads and settlements and for that he needs wood.
His parents object that she is not indian, though his father likes penny's resolute nature.
Leonard walks out to meet penny who was waiting for him in front of his apartment.
The guys return from a renaissance fair and see penny with her new boyfriend eric, leonard is approached in the caltech canteen by leslie winkle, who proposes renewing their one-time "relationship".
 although the relationship went well, even earning sheldon's approval, leonard felt uncomfortable with stephanie moving in with him, and the relationship ended.
Without telling penny, leonard and the guys go to kurt's place to recover the money.
Leonard finally reveals he actually finished his experiment a week earlier than he stated, to avoid having to drive sheldon to work.
Leonard replies that he is not just some kind of nerd but that he is the "king of nerds".
Shocked penny confesses that she will always have feelings for him and that he always over thinks everything.
She tells him what if they go out again and she ends up doing something stupid like dumping him again.
Leonard decides that, despite the fact it seems that the relationship will once again end badly, he still wishes to ask penny out.
Leonard said he did not so sheldon gives him and tells him to go back and buy some beef jerky.
Penny rubs her large pregnant belly and tells him that it is too late to start saying "no" now.
In it, she sees herself in a wedding dress and heavily pregnant with leonard at the alter.
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.
Leonard pretends he does not know penny, calls her "polly", and asks her to tell about herself.
Sheldon ignores the question and instead asks leonard what he thinks if humans evolved from lizardsinstead of mammals.
The third season premiere, leonard and penny finally started a romantic relationship and had intercourse for the first time.
It is unclear whether or not leonard has noticed this, though he clearly is still interested in penny.
Says "so insecure" to bernadette similar to how she said "so needy" to penny in "the toast derivation" (s4e17).
With the start of season 6, he wants a reluctant penny to define their relationship in "the date night variable".
Leonard arrives home the next morning, whereupon penny recognizes his "walk of shame" and sheldon thinks leonard has a future in becoming a gigolo to rich ladies in exchange for donations.
Reference: the title refers to the hypothesis leonard has that he and penny should go on a date, or perhaps even recombine as a couple again.
Dinner leonard asks penny whether there is a name for a first-date with someone you used to date and penny replies "awkward.
 subsequently, they break up because penny felt she was not as smart as leonard would like.
Episode begins with sheldon receiving a cardboard cut-out of spock he ordered, however is dismayed to find it is not the spock played by leonard nimoy but rather zachary quinto.
Penny says she was scared back at the restaurant when she thought things were going too fast.
Later, leonard sneaks back into his apartment, only to encounter sheldon, who comes out from the bathroom.
As seen in the season 1 episode "the hamburger postulate", he and leslie winkle practice their instruments and then leave to have intercourse, which leonard calls "a little musical foreplay".
After the fight, the guys learn that alicia is sleeping with one of the csi producers, leading penny to comment that alicia is a "dead whore on tv, live one in real life".
In penny's bedroom, as she is choosing an outfit to wear to the date, amy tells her that if she gets back together with leonard, they can go on a double-date with her and sheldon.
Another occasion, when leonard's mother was visiting, he and penny came very close to having sex, but leonard ruined the moment by suggesting that they were burying their lifelong issues with their parents by doing so, which offended penny.
Penny out on a spur-of-the-moment romantic dinner for two, as they contemplate renewingtheir relationship in spite of the discouragement of his friends.
Gablehauser and being given an assistant, so all the guys ditch him, and he invites penny to his people reception.
Their dispute escalates, with sheldon blocking penny's wi-fi access and penny sabotaging sheldon's laundry night.
Leonard seriously tries to move into penny's apartment though sheldon has serious objections and makes them compromise to spend multiple nights a week in leonard's old room.
Leonard is an experimental physicist, who shares an apartment with colleague and best friend dr.
Leonard explains that sheldon, despite his tendency to alienate others, kept quiet about leonard's destruction of the elevator.
Leonard then tries approaching her figure within the game, but she merely beheads his figure.
Leonard and raj take him on a trip to las vegas, nevada to cheer him up.