This is a borderline-RPG issue, in that I was just sitting here thinking about a new campaign, and had the two opening lines of a "campfire story" pop into my head. But that's it, just the first two lines. So I figured hey, throw it out there and let people play with it, see if just based on the opening two lines they could flesh it out a bit on their own. Maybe see how different RPers respond to the same base input and where they take it. Not exactly a "collaberative story" thing, per se, but a "Where would you go from here." exercise I guess. Give it a shot, if you're of a mind. You could detail the adventure from this point, or finish the story, or whatever, if anything, strikes your fancy. Just for fun:
 
"There is a story about those mountains over there. Told around the campfires of the Scattered Tribes, it relates how the great hunter Twelve Bows ended the threat of the ancient Bear God Urk."

When the sun was young and no stain was upon the moon, Urk, the Great Bear, roamed the slopes of the Daggerdells.

Now in those days men did not possess the secret of fire, or of working wood, or of any other craft.

And Urk was lord of the land, for without fire, spear, or bow, men were no threat to the Great Bear, and he took what he wished and killed when he wished, without mercy or consequence.

And Oolash was lord of the sea, for without canoe or spear or net, men did not trouble the Crashing Wave, and she flowed where she wished and stormed when she would, without kindness or curse.

All this was observed with great interest by the youngest of the Gods, who had no domain to call his own and who in later days Men called the Trickster. With a sickly smile he begun to weave secrets into the dreams of Man.

Regards,
David R