Monica's excitement about her new place of work doesn't really phase Chandler, until she mentions that one of her co-workers (Jeffery) is the funniest guy she's ever met. Chandler tries to prove he's funnier. Phoebe and Mike take the next step in their relationship, by exchanging apartment keys. Then Phoebe's old flame, David (The Scientist Guy), comes to town from Minsk for a few days, putting Phoebe's emotions in conflict. Rachel and Ross hire a male nanny (Sandy) to care for Emma, but he's too sensitive for Ross's comfort. Joey learns life lessons from the nanny's puppet shows.
Chandler [to himself in the hallway]: Funniest guy she's ever met? I'm funny, right? What do you know, you're a door! You just like knock-knock jokes! Ha-ha-ha. Save it for inside.
Chandler: Hey! I need you to set me up for a joke. Later, when Monica's around, I need you to ask me about firetrucks.
Joey: Oh, I don't know, Chandler, I'm not so good with remembering lines.
Chandler: Well, thank God you're livelihood doesn't depend on it.
Joey: Hey, did you tell Chandler that some guy from work is the funniest guy you ever met?
Monica: Yeah, so?
Joey: Really? Do you not *know* Chandler?
Joey: Being funny is Chandler's thing! You know, like Ross's thing is....
Ross: Science? Academia? Being a good father?
Monica [to Chandler]: Honey, you know I think you're hilarious! Come on, you know that joke you told last week? The one
about Jerry Lewis and the girl with the lazy eye? It slayed me!
Ross [to Chandler]: Hey, I made up that joke and told it to you!
Joey: Not knowing when to shut up.
Ross: Yep, that's my thing.
Rachel: I can't watch. It's like firing Elmo.
Sandy [as unnamed puppet]: And what's the one kind of boat they can never, ever sink?
Joey [as Mr. Wigglemunch]: What kind?
Sandy [as puppet]: A Friendship.
Joey: Wow, you blow my mind.
Sandy: Oh, I gotta go.
Joey: Oh, how much do I owe ya?
Sandy: Twenty bucks.
Joey: It's like the cheapest college ever!