Leonard: (To Raj) Dig deep! Like when we bet you couldn't fit into Howard's pants!

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Amy: What is this?
Sheldon: I'm mapping basic topics of conversation and with whom they can be discussed.
I call these circles "Zones of Privacy". Don't Google that unless you want to see pictures of people's genitals.

Bert: I met her on G-Harmony. That's a Web site for geologists to find love.
Amy: That's a real thing?
Bert: Yeah. Their slogan is "We're all about dating and not the carbon-14 kind".

Bert: Hey. Looks like I got stood up, so I'm gonna head out.
Amy: Oh, no. Are you sure you don't want to give her a few more minutes?
Bert: Nah, G-Harmony recommends after two hours, it's time to cut bait.