You have to get so 'meta' with old jokes these days and play with the structure rather than the content. But often it doesn't work too well, as in the inversion transformation applied - for example - to the lightbulb family:
"How many lightbulbs does it take to change a people?"
Very deep, very Zen, but not funny.
In fact if you see that turning up as a slogan in the near future, remember you saw it here first. Maybe one of those new philips ads - re which I'm prompted to ask who their new non-claustophobic MRI scanner ad is aimed at, exactly? "Oh, and I'll take one of those MRI scanners" - as the shopper said at the Comet checkout.
I expect they'll deliver.