Leonard and Sheldon meet Dennis Kim, a 15 year old childhood prodigy that makes them question their intelligence, especially Sheldon.
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Being the little nut job that he is, Sheldon runs a few tests after Penny comes back from Nebraska with a cold.
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Sheldon and Leonard both sit together sick on the couch with no one to take care of them.
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Sheldon has one of his co-workers post as his non-existent cousin, Leo, in order to get out of seeing Penny in Rent.
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Sheldon tries to attack Leonard with his mind when he goes to give a presentation that Sheldon does not approve of.
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Penny practices bar tending on the boys in order to learn up for her new job that will help earn her some extra cash.
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Raj gets extremely nervous and anxious after his parents set him up for a blind date with a girl from his childhood.
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As Leonard and Raj go to get Wolowitz from his house for their Halo team they overhear his mother fighting with his new girlfriend.
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Penny joins the boys for a game of Halo and they're a little shocked that she's not bad at the game.
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A picture of Leonard and Penny kissing in costume after Penny's ex-boyfriend is a jerk to Leonard at her Halloween Party.
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Sheldon and Leonard open the door at Penny's Halloween Party dressed like quite the nerds as Penny's large friend enters the apartment.
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Leonard, Sheldon and Raj sit on the couch at Penny's Halloween Party all dresses in costume.
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TBBT Quotes

Penny: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.

Penny: Here's a question-- as an alien pretending to be human, are you planning to engage in any post-prom mating rituals with Amy?
Sheldon: There are post-prom mating rituals?
Penny: Not always. Unless your date drives a van with an air mattress, then always.
Sheldon: Well, if it's part of the prom experience, then I'm open to it.
Penny: You're kidding.
Sheldon: I may be an alien, but I have urges.If Amy wants to copulate by firing her eggs into space, well, then, I will happily catch them with the reproductive sac on my upper flermin. I'm not the best at reading facial cues, but I can see that you're a little turned on.