[darech76]

Hohoho, Paladin77!

Here are my contributions.

HIM: Can I take you out for coffee sometime?
HER: You just convinced me to be caffeine-free.
or
HER: Ew! With a zit like that you'd better lay off coffee.

HIM: Can I give you a ride?
HER: Sorry, I walk faster than you drive.

HIM: Can I buy you a drink?
HER: Only if I can puke on you afterwards.
or
HER: Why? You look cooler drinking alone.

HIM: Did anyone tell you that you look like (celebrity)?
HER: I'm offended. I hate her.
or
HER: That only means I'm out of your league.

HIM: Can I have this dance?
HER: Only if I can break your toes and kick your shins. Hard.

HIM: I'd do anything to go out with you.
HER: Really? Try not going out with me.

HIM: Your face would launch a thousand ships.
HER: Too bad yours would sink a thousand ships.

***

I'll put in more if I can think up of others. Got inspired by Monkey Island 2.