A few of us used to have The Caravan Club, nothing to do with mobile homes - the object was simply to collect as many versions of Juan Tizoll's Caravan as possible - from Duke Ellington to Martin Denny to The Mills Brothers astonishing acapella version. Of course there's never an end to such a pursuit: there are many such things in the feral realm of Truly Popular Culture that go on replicating themselves imperfectly ad indefinitely by way of entropy & re-invention. Folkies think of this as the Folk Process, but those of us in the real world just see it as integral aspect of the merry continuities of Life and Art.

One thing that's always intrigued me is the story known as Jack and the Good-helpers. In this tale, the eponymous protagonist assembles a gang of uniquely skilled individuals - the fast runner, the deep listener, the strong man, the man who can control the elements etc.   Now, I've come across countless collected versions and variants as far afield as Hungary, the Welsh Gypsies and Norway, and in everyone there is a flying boat - at least a boat that can go as well on land as it can in water. Sometimes this boat is incidental to the yarn (as it the Welsh Gypsy version collected by John Sampson) other times it's the whole point of the story - as in the Norwegian version. In this folk tale we have the roots of the yarns of Baron Munchausen - and the boat is there in Terry Gilliam's 1988 film.

Such frameworks exist for the creative mind of the storyteller to set to work on. As a storyteller myself I'm conscious of working creatively within the story, especially in a performance, but I never set foot beyond its parameters. There is a little Norwegian folktale I became familiar with as a kid called 'The Boy and the Devil' in which Jack (or Espen / Boots) manages to trap the devil in the shell of a hazel nut which he then gives to the blacksmith, thus giving the devil a good thrashing and ends the story with some verbal pyrotechnics and the droll punch line from the unwary blacksmith: 'The Devil himself must have been inside that nut!'

I've been telling the story myself for decades - expanding it from a few hundred words to a good twenty-minutes, but never once going beyond the bounds of the story. Raymond Greenoaken got it off me but found he couldn't get a laugh with the traditional ending, so he began to elaborate (with typical cunning I might add) outside of the framework. From Raymond it went to Richard Walker, AKA Mogsy, (RIP) who used it for his Jack and the Magic story. And so it goes on, and on, but the story remains at its most fundamental and traditional enshrined in the pages of Asbjorsen and Moe (I got in A Time For Trolls in Norway in 1969) waiting to be taken up afresh. Indeed it even links in with Duncan Williamson's epic 'The Boy and Death' which you'll find in his Penguin Folklore Library volume.

Incidentally the The Broonie, Silkies & Fairies: Traveller's Tales of the Other World mentioned by DeepDoc1 above is also a collection of Duncan Williamson stories. Always credit where credit is due.