Here is a sampling of actual quips I've recieved had over the past few years along with some answers that worked.

Quip - What's up with the skirt?
Retort - What's up with the bad haircut?

Quip - Where's your bagpipes?
Retort - Same place as yours. (To a man)
- Same place as your fathers' (to a woman)

Quip - So are you gay or what?
Retort - Sorry... You'll have to look elsewhere!

Quip - Nice skirt!
Retort - It should be for $500.

Quip - Are you scotch?
Retort - No but I drank some last night!

Quip - Are you a "true Scot"?
Retort - Is there any other kind?

Quip - Are you playing bagpipes today?
Retort - No, but I'm playing poker later!

Quip - Did you lose a bet?
Retort - I won... the loser has to wear jeans!

There's a few others I can't remember at the moment. I find that most quips are pretty stupid and mostly confined to the "skirt - bagpipe" group. Easily demolished.