Leonard [about the time machine]: The lights flash, and the dish spins. You wanna try it?
Penny: No, I don't wanna try it! My God, you are grown men! How could you waste your lives with these stupid toys and costumes, and comic books, and-and... now that-that...
Sheldon: Again—time machine.
Penny: Oh, please, that's not a time machine. If anything, it looks like something Elton John would drive through the Everglades

Penny [to Leonard]: Look, you are a great guy, and it is the things you love that make you who you are.
Wolowitz: I guess that makes me large breasts

Sheldon: I propose we add "pants must be worn at all times in the time machine"
Leonard: Seconded.
Wolowitz: I was gonna put down a towel

Sheldon: Are you upset about something?
Leonard: What was your first clue?
Sheldon: Well, it was a number of things: first, the late hour; then your demeanor seems very low energy; plus your irritability...
Leonard: Yes, I'm upset!
Sheldon: Huh, I don't usually pick up on those things. Good for me.
Leonard: Yeah, good for you.
Sheldon: Oh, wait, did you want to talk about it?
Leonard: I don't know, maybe.
Sheldon: Wow, I'm on fire tonight

Sheldon: You hypocrite!
Penny: What?
Sheldon: Little Miss 'Grown-ups don't play with toys', if I went into that apartment right now, would I not find Beanie Babies? Are you not an accumulator of Care Bears and My Little Ponies? And who is that Japanese feline I see frolicking on your shorts? Hello, Hello Kitty!

Leonard: Girls like Penny never end up with guys who own time machines.
Sheldon: I disagree. Your inability to successfully woo Penny long predates your acquisition of the time machine. That failure clearly stands on its own.
Leonard: Thanks for pointing it out.
Sheldon: In addition, your premise is flawed. In the original film, Rod Taylor got Yvette Mimieux with that very time machine. In Back to the Future, Marty McFly got the opportunity to hook up with his extremely attractive young mother.
Leonard: Those are movies.
Sheldon: Of course they're movies. Were you expecting me to come up with an example involving a real-life time machine? That's absurd

Leonard: The elevator's been broken for two years.
Sheldon: I've been meaning to ask you. Do you think we should make a call about that?
Wolowitz: Not necessary. I have a Masters in Engineering. I remotely repair satellites in a regular basis. I troubleshoot space shuttle payloads. When the Mars Rover started pulling to the left I performed a front-end alignment from 62 million miles away. [pushes the button...] No, that baby's broken

Leonard: Come on, guys, push!
Howard: If I push any harder I'm gonna give birth to my colon.
Raj: I can't feel my fingers. Hurry up!
Sheldon: It's the same amount of work no matter how fast you go—basic physics.
Raj: Sheldon, if my fingers ever work again, I've got a job for the middle one

Sheldon: Why'd you set it for the day before yesterday?
Leonard: Because I want to go back and keep myself from getting a time machine.
Sheldon: You can't. If you were to prevent yourself from buying it in the past, you would not have it available in the present - travel back and stop yourself from buying it, ergo you would still have it. This is a classic rookie time travel mistake.
Leonard: Can I go back and prevent you from explaining that to me?
Sheldon: Same paradox—if you were to travel back in time and, say, knock me unconscious, you would not then have the conversation that irritated you, motivating you to go back and knock me unconscious.
Leonard: What if I knocked you unconscious right now?

Raj: Too bad, I called dibs.
Wolowitz: You can't just call dibs.
Raj: I can, and I did. Look up "dibs" in Wikipedia.
Sheldon: Dibs does not apply in a bidding war

The Big Bang Theory Season 1 Episode 14 Quotes

Sheldon: Why'd you set it for the day before yesterday?
Leonard: Because I want to go back and keep myself from getting a time machine.
Sheldon: You can't. If you were to prevent yourself from buying it in the past, you would not have it available in the present - travel back and stop yourself from buying it, ergo you would still have it. This is a classic rookie time travel mistake.
Leonard: Can I go back and prevent you from explaining that to me?
Sheldon: Same paradox—if you were to travel back in time and, say, knock me unconscious, you would not then have the conversation that irritated you, motivating you to go back and knock me unconscious.
Leonard: What if I knocked you unconscious right now?

Raj: Too bad, I called dibs.
Wolowitz: You can't just call dibs.
Raj: I can, and I did. Look up "dibs" in Wikipedia.
Sheldon: Dibs does not apply in a bidding war