Penny: No, it does matter. Okay? You were right. It was Halloween. I was dressed as a cat, you were a hobbit. It was right there on that couch.
Leonard: Why didn't you just say that?
Penny: Because I always hated that was our first kiss. I was drunk, and I was still with Kurt, and I was using you to make myself feel better. I just wanted our first kiss to mean something. That's why I said it was the one on your birthday.
Leonard: I like that. We'll make that our official first kiss.