Leonard: On the other hand, I think Sheldon might be the larval form of his species, and some day he'll spin a cocoon and emerge two months later with moths wings and an exoskeleton.
Penny: Okay, well, thanks for the nightmares.

Leonard: Oh, then I think you'll appreciate what I got you.
Penny: Okay. 101 Totally Cool Science Experiments for Kids.
Leonard: You know, 'cause you're so into science.

Dave: I don't know how you live next door to that without doing something about it.
Leonard: Actually, science is my lady.

Leonard: I've been offering to show you around for a year and a half. You always said you had yoga.
Penny: I never said that.
Leonard: Maybe I heard you wrong. A lot of words sound like yoga.

Sheldon: Let me point out that two degrees can be the difference between water and steam.
Leonard: Yes, if we lived in a tea kettle.

Leonard: Look, I am in the Halo battle of my life here. There's this kid in Copenhagen. He has no immune system so all he does is sit in his bubble and play Halo 24/7.
Howard: Can't you play him some other time?
Leonard: Not if you believe his doctors.

Leonard: Here you go, Copenhagen boy, how about a taste of Hans Christian Hand Grenade.

Leonard: Ladies,
Emily: Are you being polite or scared?
Leonard: Yep.

Amy: I just read about an experiment designed to see if you can make two people fall in love in a matter of hours.
Leonard: That doesn't sound right. My research has shown it takes three to five years of shameless begging.
Penny: Honey, neither of us comes off good in that story.

Leonard: Wow, teasing the guys at the Apple Store seems a little redundant now.
Sheldon: I don't follow.
Leonard: I wouldn't expect you to.

Sheldon: I fashioned historically accurate undergarments out of linen.
Leonard: You went out and bought linen?
Sheldon: Don't be silly, I borrowed one of your pillow cases.
Leonard: Borrowed?

Leonard: I just keep thinking how cool it would be if I called my mom and told her that I got tenure at Caltech.
Penny: She'd be proud, huh?
Leonard: Oh, very. Assuming she takes my call.

Leonard: Oh, cool. I've got a lawyer. And I've seen her naked.

Leonard: No offense, but shower sex with you is now the second best thing that's happened today.

Leonard: Sheldon took our order.
Penny: Sheldon doesn't work here.
Leonard: Well, honey, not to complain, but we were starting to think you didn't either.