Gordon the clown and his party balloon

No point in having an economy if you can't explain it to the eight year old who will one day have to pay for it all.

Once upon a time an old witch called Thatcher was given a balloon. She knew what it was, and - to the disgust and disagreement of almost everyone watching - stuck a piece of tape over the chosen spot before blithely inserting a sharpened finger nail and letting the balloon down slowly. The people watching didn't enjoy the balloon deflating, but they were glad later on when the hole could be fixed and the balloon used again. Perhaps she wasn't such a witch after all.

Some years later, along came a clown who thought he was a magician. Gordon told the children he was much cleverer than the old witch had been - and blew and blew and blew into the balloon, to the delight of all of those watching. "I've performed a magic trick" he shouted to the assembled children, "this balloon can never burst". And he blew some more.

And then, when the inevitable happened, and the balloon burst into a thousand shreds - he blew even harder into the mouthpiece. "No, really" he shouted at the frightened children. "Just watch this - if I blow some more the balloon will come back together". "Honest!".