Howard: I just realized, now that I'm not in the band, I can focus on my own music. You know, go solo.
Bernadette: You said you were taking a break from the band to help with me and the baby.
Howard: Yes, and write an astronaut musical. Picture this. The curtain opens. There's a lone astronaut floating in the inky blackness of space. Maybe wires, maybe fog. I'll let the director figure that out. [playing the keyboard] "I really don't know when I'll run out of oxy gen".

Howard: Good news! I'm back in the band!
Raj: So, Bernadette doesn't mind?
Howard: It was her idea!

Penny: So it's sort of like a guitar string, but instead of making an actual sound, each vibration is a different particle?
Sheldon: Precisely. And when you express it in 11 dimensions, Einstein's relativity equations pop out. Does that sound like a coincidence?
Penny: It does not.

Penny: So, so, did we do it? Did we just solve string theory?
Sheldon: Oh. (laughs) I appreciate your enthusiasm, but this is not the sort of thing we can figure out in a night. People have been stuck on this for decades.
Penny: What, decades? Really? It's-it's a string. How hard can it be? It's straight, it's in a loop, it gets knotted up with other strings.
Sheldon: Well, actually there are no knots in anything greater than four dimensions. Ooh, unless we get around that by considering them as sheets. You know, topologically speaking, that has a lot of interesting possibilities.
Penny: See? How long did that take me, like a minute?

Raj: Toby, today you are a man, and you will face many obstacles in life.
Bert: And some of those obstacles are gonna feel like boulders.
Howard: This first song is about the greatest boulder in the history of cinema.

Amy: Oh, Leonard.
Leonard: Sorry, I just, I had to get out of there.
Amy: What did he do now?
Leonard: Nothing. He's being a dream. Don't give me that look. That's how Penny looked at me. I'm not crazy.

Amy: Penny and I have the same "You're crazy" look? That's kind of sweet.

Leonard: I know how to deal with Sheldon being Sheldon, but Sheldon being a-a rational, thoughtful person? I'm clueless. It's like when my mom called last year to sing happy birthday and I-I just threw up.

Sheldon: See, I'm trying this new technique where I imagine how I would feel in someone else's position.
Amy: Y-You mean empathy?
Sheldon: Oh, I thought I came up with it.

Raj: Space is the mirror of the soul. Are we looking beyond, or are we looking within?
Leonard: I'm looking at my shoes. This is making me a little motion sick.

Nell: Hey. Can I get a picture with you?
Raj: Absolutely. And if you post it on social media, I suggest the hashtag "Koothra-poet."

Nell: Thank you. The show was great.
Raj: Well, I can't take all the credit. I have pretty good co-stars ... the stars.

Nell: Do you say that to everyone?
Raj: Only to beautiful women. And okay women.
Nell: Okay.
Raj: Uh, just to clarify: you're the first kind.

Raj: Thanks for coming. What did you handsome gentlemen think of the show?
Leonard: Uh, you can turn it off now.
Raj: It's sweet of you to say, but I don't think I can.

Howard: What are we looking at here?
Raj: Well, that's me and a beautiful woman and my watch showing the time as 2:30 in the morning.
Howard: So, state's "Exhibit A"?