Responding to Spontaneous Situations

Inviting / Offering
How about meeting on Friday?
What about meeting on Friday?
Do you feel like meeting on Friday?
Would you like to meet on Friday?
Do you want to meet on Friday?

Accepting
I'd love to.
Good idea.
Why not?

Partly accepting
Maybe... Can I let you know later?
Let me just check with my boss / my wife.
OK... But I can't stay long.
Yes, but can we make it next week?

Declining
Sorry, I'm heading straight home tonight, it's my wife's birthday.
Not tonight, I've had a bad day.
I'm afraid I don't really feel like it today.
I'm afraid I need to stay behind and finish this presentation.