Do any of you have any tips for dealing with a broken string (let's say guitar, that's my main instrument) in mid-set, assuming you don't have a spare instrument to hand?

If I do a floor spot (say 2 or 3 songs) it's not such a problem, as I can usually think of a few songs to do unaccompanied. But for a longer set, it would be a nightmare if it happened near the beginning.

Ideas I've thought of:

1. Restring while telling a joke
2. Restring while singing unaccompanied
3. Just apologise, explain the problem and restring without saying anything much, so you can concentrate on the job and get it done more quickly.

I'm not sure I could do 1 or 2 very well as I feel I'd need to watch what I'm doing - but I guess if it happened often you'd get good at it, like everything else.

I always carry spare strings but not always a spare instrument. The latter would be ideal, but it seems a bit over the top to have to carry two of everything.

This hasn't actually happened to me yet, but sooner or later it will.

Anyone got any good tips?