Triskelion said:
Kirk to Spock, there's a cat in my ceiling.

This really goes well with Kirk's expression...
Captain Jack Harkness had not been the first to find out that a defabricator does exactly what it says on the tin.
Kirk (into intercom): Am I naked in front of millions of viewers?
Spock: Absolutely.
Only Jack Harkness had taken the news slightly better.
---
I believe this one has already be done on another contest, but well, here it goes:
SPOCK: Bring out your dead! Bring out your dead!
MCCOY: Here's one -- nine pence.
VAN GELDER: I'm not dead!
SPOCK: What?
MCCOY: Nothing -- here's your nine pence.
VAN GELDER: I'm not dead!
SPOCK: Here -- he says he's not dead!
MCCOY: Yes, he is.
VAN GELDER: I'm not!
SPOCK: He isn't.
MCCOY: Well, he will be soon, he's very ill.
VAN GELDER: I'm getting better!
MCCOY: No, you're not -- you'll be stone dead in a moment.
SPOCK: Oh, I can't take him like that -- it's against regulations.
VAN GELDER: I don't want to go in the cart!
MCCOY: Oh, don't be such a baby.
SPOCK: I can't take him...
VAN GELDER: I feel fine!
MCCOY: Oh, do us a favor...
SPOCK: I can't.
MCCOY: Well, can you hang around a couple of minutes? He won't be long.
SPOCK: Naaah, I got to go on to Robinson's -- they've lost nine today.
MCCOY: Well, when is your next round?
SPOCK: Thursday.
VAN GELDER: I think I'll go for a walk.
MCCOY: You're not fooling anyone y'know. Look, isn't there something you can do?
VAN GELDER: I feel happy... I feel happy.
[SPOCK slaps VAN GELDER]
MCCOY: Ah, thanks very much.
SPOCK: Not at all. See you on Thursday.
MCCOY: Right.