I believe that was an ad-lib, too.
I’m not sure I get the mousse joke. Was that a reference to Holy Grail?
More from AD. After getting back from Mexico:
Lindsay: “Hey, you’re back already.”
Michael: “Yeah, we won.”
I laughed for 5 minutes…
Watching an old Buffy last night Willow has just come from tending to a very ill Angel. She is talking to Oz, who is very low-key:
Willow: “He thought I was Buffy.”
Oz: “You too, huh.”
From last week’s episode of Royal Pains:
“I just spent all day trying to convince those girls that I wasn’t a douchebag but then I sent them home smelling like vinegar and water.”
When Harry Met Sally
‘I’ll have what she’s having.’
From Monsters vs. Aliens:
“Oh man it’s hot. Did it get warmer out since we were in prison? Cuz that would be a really convenient truth.” I laughed so hard at that, and nobody else did.
Another Simpsons, from that all time classic “Homer’s Phobia” when Homer is driving through Santaland and hits a deer:
Homer: D’oh
Lisa: A deer
Marge: A female deer
Sealab 2021. Two guys out swimming in the ocean. One gets eaten by a shark. The other? “So long, chum!”
I remember that scene. Laurie’s delivery is simply perfect, it really made me laugh.
Nitpick: That’s from Bart Gets an Elephant. Homer was driving through a tar pit.
The first episode of Firefly, the much not-as-loved-as-other-episodes The Train Job, had a couple of gems:
Mal: [backed up against the edge of a cliff, facing the drunks from the bar] Oh, ho-ho! There’s just an acre of you fellas, isn’t there? This is why we lost, you know. Superior numbers.
Zoë: Thanks for the reenactment, sir.
Wash: Did he just go crazy and fall asleep?
Crow: Keep the money. Use it to buy a funeral. It doesn’t matter where you go or how far you fly. I will hunt you down, and the last thing you see will be my blade.
Mal: Darn. kicks Crow into running jet intake FWOMPHSSSS
Another House gem:
They have to give an endoscopy to a patient, but for some reason can’t use any sedatives of painkillers, and Cameron is objecting.
Cameron: Do you have any idea what it feels like to have a six foot tube shoved up your rectum?
House: No, but now I have a lot more respect for whatever basketball paper you dated in college.
My all-time favorite throw-away line is from The Godfather: “Leave the gun, take the cannolis.”
For my money, when you’re talking about funny lines in The Godfather, you can’t beat
In The Godfather, my favorite was:
“Why don’t you tell that nice girl how you feel, Micheal? I love you, I miss you, if-a I don’t-a see you a-soon I’m-a-gonna die!”
The Godfather was funny?
You must have forgotten this scene. 
(Sorry about the commercial before the video.)
“I have a position for you on my penis.”