The Justice League Recombination

"The Justice League Recombination" is the eleventh episode of the fourth season of the   The Big Bang Theory. This episode first aired on December 16, 2010.

Summary
The guys get Zack and Penny to join their Justice League costume group for a bash at the comic book store to win the best group costume prize. Penny is going as Wonder Woman, while Zack dresses as Superman.

Extended Plot
The guys discover that Penny and her ex-boyfriend, Zack, are back together and they take advantage of his lack of intelligence and make fun of him. After Zack finally realizes what's going on and storms out, the guys decide to apologize to him and give him some. Zack immediately forgives Leonard and his friends and goes with the guys to the comic book store, leaving Penny behind. At the store, the guys realize that Zack would be great as Superman for their Justice League group at Stuart's New Year's Eve costume party, who would replace short Leonard as that role.

Leonard agrees as long as he goes as Green Lantern, leaving Raj to be Aquaman, much to his distress. They return home with the Justice League costumes, with Howard being Batman, Raj as Aquaman, Sheldon as The Flash, and Leonard as Green Lantern. They even purchase a Wonder Woman costume for Penny. However, Penny doesn't want to go and suggests that they ask Bernadette or Amy, but Howard says Bernadette is under quarantine and Sheldon says Amy doesn't believe in wearing costumes, leaving no choice but for Penny to go.

On the night of the party, the guys arrive at the apartment in their costumes. Sheldon as the Flash is pacing back and forth though Leonard says that it looks like he's jogging. Sheldon replied by saying, "This is how The Flash paces". But Penny refuses to wear the black wig and eventually refuses to even go to the New Year's Eve costume party at the comic book store after Zack embarrasses her. None of the guys, not even Zack, can convince Penny to go. Since Zack would not go without Penny and the Justice League wouldn't be complete without Superman and Wonder Woman, Sheldon says that they'll have to go in their costumes, but then they make Leonard talk to Penny.

Penny reveals that she is only with Zack because she doesn't want to be alone for New Year's Eve. It is hinted that she still hasn't fully gotten over Leonard. Penny relents, puts the wig on to avoid the "Leonard " question, and the group later wins the costume contest.

When midnight strikes and it becomes the new year, 2011, Zack is kissing Penny, she looks guiltily over at Leonard for the duration of the entire kiss, while Leonard gazes back at her. The episode concludes with the group witnessing an ongoing car theft on the way back home and despite wearing Justice League costumes, they comically scurry off, none of them, not even Zack, are brave enough to stop the car theft.

That New Year's Day evening, Leonard warns Sheldon that he wants to change the thermostat temperature. Sheldon then imagines himself as The Flash, speeding to the to scream in frustration. Once he is "back", Sheldon tells Leonard, "Fine".

Critics

 * The TV Critic: "This failed on pretty much every level which was a shame. In theory I applaud the idea of focusing on Penny and Leonard's relationship, but there is no authenticity to it anymore. The writers have made less and less effort to demonstrate any actual bond between them. Leonard still treats her like she is too good for him and her feelings for him have returned out of nowhere. The result is that her emotions seem fabricated and the story falls flat...What often saves The Big Bang Theory from being a lame duck is the sharpness of its writing. In this case the writing was lazy and the result was a lousy episode which felt as phoned in as Penny's feelings for Leonard ."
 * The A.V. Club gave this episode an A-.
 * IMDb user reviews

Trivia

 * The Justice League consists of
 * Sheldon as: The Flash
 * Leonard as: Green Lantern
 * Howard as: Batman
 * Penny as: Wonder Woman
 * Zack as: Superman
 * Raj as: Aquaman
 * Sheldon asks in what universe is Wonder Woman blonde, in fact starred as a blonde Wonder Woman in the unsuccessful 1974 TV movie "Wonder Woman" Also in a  storyline "Titans Tomorrow" Cassandra Sandsmark aka, who was a blonde, was shown as Wonder Woman's successor.
 * Raj once went to a  camp, and had a penis drawn on his face by bullies there. Refer to "The Speckerman Recurrence" for more on bullies.
 * Stuart reveals that he earns around $1.65 an hour, $6.35 below the minimum wage in Pasadena, California, though Stuart owns the stores and that is based upon the long hours he puts in and not a salary.
 * Raj reveals he hates Aquaman in this episode. In "The Spaghetti Catalyst", Raj stated, "Oh, please, we all know I’m the friend you call when you have no other options. If we were the Justice League, I’d be Aquaman." He also mentioned Aquaman in "The Precious Fragmentation" and "The Robotic Manipulation".
 * Some species of have the ability to regenerate lost arms and can regrow an entire new arm in time. Sea stars can grow an entire sea star from a single ray.
 * Bernadette is apparently under quarantine for this episode, as at her lab Christmas party she took jello shots from a petri dish that used to contain Yellow Fever. This was revealed by Howard when the guys asked why she couldn't be Wonder Woman.
 * At the costume party, Stuart is dressed as Doctor Who from the BBC series Doctor Who.
 * When Penny is talking to Leonard in her apartment, this is the closest that she ever comes (at this point) to telling Leonard how much she feels for him. Penny refers to "The Middle Earth Paradigm" when she states to Leonard, "Look, if Zack and I had just gone to a regular club or a party, it would have been fine, but this, with the costumes, and you."
 * The costumes the cast choose reflects their character:
 * ​Howard as Batman - Howard is an engineer and has built a lot of high-tech gadgets, such as an engineer might make.
 * Raj as Aquaman - In comic books Aquaman is the King Of Atlantis and spends a lot of time being classified as an outsider. Raj as a foreigner sometimes doesn't understand American culture and is an outsider in other ways.
 * Penny as Wonder Woman - Fairly self explanatory. She is Leonard's Wonder Woman.
 * Leonard as Green Lantern: Green Lantern is a character who uses a ring to create constructs using their will. Green Lantern users therefore must have a lot of will to be successful. Obviously Leonard has the will to work hard in his studies to become a Doctor. What is relevant though is that Leonard must have great will to put up with Sheldon.
 * Zack as Superman - He is the only one out of the group to have actual muscles.

Quotes

 * Zack: Hold on. The costume came with a black wig. Where is it, babe?
 * Penny: No. I'm not wearing it. It looks stupid.
 * Zack: Come on. We're trying to win a contest here.
 * Penny: Forget it. I'm not wearing the wig.
 * Zack: Penny. There's no I in Justice League.
 * Howard: Well, actually.
 * Sheldon: Don't. He's making our case.


 * Zack: Oh, no, you’re thinking old-school Archie. It’s much more sophisticated now. Like, there’s two universes, and Archie’s married to Betty in one and Veronica in the other. Midge is even breaking up with Moose.


 * Leonard: Look, I know our winter thermostat setting is 72 degrees, but I'm a little warmer, so I'm going to turn it down.
 * Sheldon: (as The Flash, runs to the Grand Canyon) Good lord, how you frustrate me, Leonard Hofstadter! (runs back) Fine.


 * Zack: Look up in the sky. It’s a bird. It’s a plane. I forget the rest.
 * Penny: All right. Let’s get this thing over with.
 * Sheldon: I’m sorry. But in what universe is Wonder Woman blonde?
 * Howard: Relax. No one’s going to be looking at her hair. Ow! I mean, "OW!"


 * Sheldon: (knocking door loads of times) Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny, Penny.
 * Penny: (opens door) What the hell is wrong with you?
 * Sheldon: I'm the Flash. I just knocked 30,000 times.