Penny asks Leonard if he'll be coming in to The Cheesecake Factory for his free birthday cheesecake slice. Actually, they only offer a free scoop of ice cream, with the option to purchase a specially decorated slice of cheesecake.
Sheldon: What twelve-year-old boy wants a motorized dirt bike?
Sheldon: By the way, a six-year-old can hack your computer system.
Penny: (pushing him) Keep walking.
Sheldon: 1234 is not a secure password!
Sheldon: (to an electronics customer) What computer do you have? And please don't say 'a white one.'
(Howard feigns an allergic reaction to peanuts)
Howard: We have to go to the hospital!
Howard: No, we'll wait until my tongue swells up to the size of a BRISKET!
Penny: (on Leonard's parents not considering his birthday as an "achievement" to be celebrated) That's so silly.
Sheldon: It's actually based on very sound theories; his mother published a paper on it.
Penny: What was it called, "I Hate My Son and That's Why He Can't Have Cake"?
Sheldon: It was obviously very effective. Leonard grew up to become an experimental physicist. Perhaps if she also denied him Christmas, he'd be a little better at it.
Penny: (on phone) How about this: you keep him there a little longer, and when you get to the party, I'll point out which of my friends are easy.
Howard: (long pause) Don't toy with me, woman.
Penny: I got a hot former fat girl with no self-esteem, I got a girl who punishes her father by sleeping around, and an alcoholic who's two tequila shots away from letting you wear her like a hat.
Howard: Thy will be done.
Leonard: How did you know my birthday's Saturday?
Penny: I did your horoscope, remember? I was going to do everybody's until Sheldon went on one of his typical psychotic rants.
Sheldon: For the record, that psychotic rant was a concise summation of the research of Bertram Forer, who, in 1948, proved conclusively through meticulously designed experiments that astrology is nothing but pseudoscientific hokum.
Penny: Blah, blah, a typical Taurus.
Leonard: I don't celebrate my birthday.
Penny: Shut up. Yeah, you do.
Leonard: It's no big deal. It's just the way I was raised. My parents focused on celebrating achievements and being expelled from a birth canal was not considered one of them.
Penny: Well, Sheldon you are his friend. Friends give each other presents.
Sheldon: I accept your premise; I reject your conclusion.
Howard: (quietly to Penny) Try telling him it's a non-optional social convention.
Howard: Just do it.
Penny: It's a non-optional social convention.
Sheldon: Ahh, fair enough.
Howard: He came with a manual.
Sheldon: Leonard made it very clear, he doesn't want a party.
Howard: Did someone say party?
Penny: He just doesn't know he wants one because he never had one.
Howard: I suppose that's possible, but for the record I've never had a threesome and yet I still know I want one.
Penny: Howard here's a difference: the possibility exists that Leonard could have a birthday party before hell freezes over.
Howard: Fine, if I do have a threesome you can't be part of it. (waits a minute) I'm just kidding. Yes, you can. Can you bring a friend?
Wolowitz: (trying to get an black nurse to admit him to the ER) Okay, I get it. I know how the world works. (flashes a five dollar bill) How about I introduce you to the man who freed your people?
Nurse: Unless my people were freed by Benjamin Franklin and his five twin brothers, you are wasting your time.
The German episode title is "Die Erdnuss-Reaktion", the Italian title is "La reazione alle arachidi", the Spanish title is "La reacción al cacahuete", and the Mexican title is "La reacción al maní", all exact translations. The French title is "Réaction!".
Turkey: December 30, 2008 on CNBC-e
Germany: September 26, 2009 on ProSieben
Slovakia: September 9, 2011 on Markiza
John Shaffner, Francoise Cherry-Cohen, and Ann Shea were nominated for an Art Directors Guild Award in the Excellence In Production Design-Episode Of A Multi-Camera Television Series category for their work on this episode.
This episode's end titles has Chuck Lorre's Vanity Card #210.