For what it is worth, some bits on the warm-up. No originality involved, but it goes like this;
The first thing is to play jolly music from a tape five minutes or less before starting time. Fairground organ stuff usually, but on the beach, I sometimes play jazz tapes just because I like them. It lets people know there is something going on and when it stops, you have their attention for a moment so you can jump in and call out 'Roll Up' or something similar.

As they are gathering; 'All we need is another fifty people and we can start the Show'
Immediately after;
'All we need is another thirty people and we can start the Show'
'All we need is another twenty people and we can start the Show'
'I'll settle for ten'
'Plenty of seats in the stalls, a few in the circle.'
'Traditional Punch and Judy, full of sex and violence, unsuitable for children'
This line, delivered tongue in cheek, gets approval from the adults and goes over the heads of the kids.
When you are ready; 'Who wants to see a Show?' The kids always put their hands up.
'Put your hands down, we need to have a word with the grown-ups.'
'If you are going to stay, you have to adjust to a mental age of eight, up or down as the case may be.' Pointing to a smiling gent; 'That was quick, Sir.'
'Let's try again, who wants to se a show? Most of the adults put their hands up this time. 'What nice looking children! We did a show last week and they were all ugly. ' (This nonsense produces a bigger laugh than you would expect). 'Not sure about the grown-ups.' (sotto voce) 'Let's have a count up.' Count wrongly; 1,2 ,3 ,25 ,36, 44 ,55 ,66, forty two and a half.' Kids feel superior.

'Not enough, will someone ring my bell and we can get some more people?' Lots of volunteers. Pick out suitable child and they ring the bell after you have asked them their name and age. 'Hold it with two hands because I don't want you to drop it on my foot.'
'I want someone else noisy.' Pick out another child. 'Are you sure you are noisy?' 'You look very well behaved to me, I was hoping for a football hooligan.' 'If you take your hands out of your pockets, will your trousers fall down?' (When appropriate).
'Will you do some shouting for me?' Offer the mic. and ask them to shout, 'Roll up, Punch and Judy Show just about to start.' Some will bawl into the mic. which you withdraw as if startled and say, 'you don't need this.' Get the kid with the bell to ring it a bit and then ask the noisy one to shout out, 'Roll up, Roll up, come and see the live lion stuffed with straw and the dead donkey singing.' This produces a laugh and you tell the one with the bell to ring it to cover the gap. 'That was my fault, I made it too hard.' (Don't let the kid feel discomforted) 'I'll make it easier, say Roll up, Roll up, have your voices ready please.' Praise the kids for being so good. ('I wouldn't like to live next door to you.')
'Only one thing before you sit down, when I count to three, I want you to smile at the audience. Let's see your smile (to one of them) Show some teeth. (Remarks according to the sort of smile you get) (then the other). To the audience; 'They were very good, so when they smile at you, I want you to give them a tremendous round of applause.' Count up to three, applause, ask them to sit down and go into the 'Punch is asleep, let's wake him up routine.'

Get into the booth and say, 'can you hear me kids?'. That's funny I can't hear you, can you hear me? (Terrific yell) That's better, I thought you had all gone to the pictures.
Listen......(Punch snores, if you need time to take a jacket off, or take false teeth out, etc.) He wakes and the show starts (at last!).

I have several bells in different sizes, so, if a young child comes up I can give them the 'five-year-old bell', or whatever. This is especially cute when a really small child will not let go of a brother or sister and they get a tiny bell to ring.

The bit about the live lion stuffed with straw, etc. is a genuine cry from Bartholomew Fair and I like to keep it in use.

(c) John Alexander 2003