The kids character, Thomas the tank engine, is a great example of this. It all started in 1942, with a dad telling his sick kid stories to cheer him up. The kid liked it so much, that his Dad turned it into short stories, and then books. Today there are 42 books, with the last one released in 2011, a TV show that has been running for 27 years, and kids all over the world know and love Thomas. And the little kid, now 72, is still involved in the franchise.

Full story on Wikipedia: http://en.wikipedia.org/wiki/Thomas_the_Tank_Engine