Generally, I was trying to collect stories where the hero is not young. People, regardless of age, have the potential to be the hero of their own story. In order to combat ageism, here are some stories that prove just that:
In this folktale type, popular all over Europe, and old woman (sometimes man) attempts to avoid Death knocking on her door, because she loves living so much. She manages to convince Death to come back the next day, asking him to write "TOMORROW" on the door frame. The next day, when Death returns, she points out that the sign says "tomorrow" and sends him away. Getting away on a technicality this way she continues to live, until Death erases the sign. The next day, trying to hide from her fate, she first hides in a barrel of honey, and then in the bed, turning into a honey-and-feather "monster" - when Death shows up to take her, he is so scared he never returns.
I like this story because 1. It features a female trickster, and 2. It shows that the love of life and living (and the right to fight for it) does not solely belong to the young.
(Read this story in Dan Keding's Elder tales)
By the way, Elder tales is an amazing collection of traditional stories that feature elder protagonists. Dan Keding has pretty much done my job for this post, so I'll just mention some that I particularly like.
Old woman returns fire to people
I heard this Greek folktale at the FEST conference last year, on the island of Kea. It said that God took the fire away from people for their sins, and then an angel appeared, selling burning embers for outrageous prices - years of life, eyesight, other things people were not willing to give up, even if they suffered without fire. Finally an old woman showed up, asking the angel about the prices of embers, poking at them with her walking cane. What the angel didn't know was that the cane was hollow, with straw inside, and this way the old lady managed to steal fire back to the people. This is clearly a version of the myth of Prometheus - although it is questionable which one came first, the titan or the wise old woman...
In this unusually dark Grimm tale, a princess falls into the depths of the Glass Mountain, and is imprisoned by a little old man, who threatens to kill her if she does not do his household chores. He leaves every day, and comes back with gold, but never lets her leave. The princess grows old, and the man named Old Rinkrank starts calling her Mother Mansrot. Finally one day she figures out how to set a trap for him, and rescues herself.
(Read the story here)
Old Man's Wisdom Saves the Kingdom
This is a folktale type, ATU 981, popular in several parts of the world. In it, a king orders to kill off all old people in the kingdom, either because of a famine, or just because he is crazy. One young man saves his old father/parents and hides them in a secret location. Later, when the kingdom is in trouble, the solution is provided by the elders to the young man, who manages to save the kingdom, change the king's mind, and/or become a just king himself.
(Read one version in Latin American Folktales)
Not "old," but still unusual in the world of tales - this Russian legends tells about a hero that lived at home with his parents, doing nothing, until he was thirty (or forty) - when one day he finally decided to go out into the world and be a hero. It is never too late to start out on one's hero's journey.
(I included part of his story in my book, Tales of Superhuman Powers)
What other tales should I add to the list?