Leonard: Well, this time it's going to be different. Because I am like a romance ninja. You don't see it coming and then, bam, romance. Watch out! Hearts, kisses, love, ooh-ya!
Penny: You know, sometimes I think I've made you so much cooler than you used to be, and then you go and do something like that.

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Leonard: What am I supposed to do?
Penny: Err, keep your mouth off other women.

Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.

Howard: She hid my XBOX like I'm a child. And my mom got me that for my birthday so if you don't give it back, I'm telling.

Bernadette: If you like pushing buttons so much, try pushing them on the washing machine.

Howard: A micro-valentine for a microbiologist.
Leonard: From her micro-husband.