Barney: Ah, ah, Lily. I heard this great joke at work.
Ted: Dude, come on. She's not gonna like it. It's boy-funny. It's not girl-funny.
Barney: That is sexist! Funny is funny, Ted. Lily's cool. She'll appreciate this.
Marshall: Oh, you're on your own, man.
Lily: Just tell me the joke.
Barney: Okay. Ready? Lily, what's the difference between peanut butter and jam? See? It's funny.
Ted: It's boy-funny.
Marshall: She's not gonna like it.
Lily: Why don't you let me decide? What's the difference between peanut butter and jam?
Future Ted: [v.o.] And then Barney said the punch line. To this day, it's still the dirtiest joke I've ever heard in my life. And no, I'm not gonna say it.
Lily: Yeah, I can't hang out with you anymore.
Barney: Oh, come on. That's a funny joke. That...
Ted: Told you.
Barney: She'll be back.
Future Ted: [v.o.] And we didn't see Lily for four weeks.