A world where, instead of aging in years, the people age in knowledge. So, instead of dying once a general age was reached, they die once they achieve a certain amount of knowledge. A man could live forever if he never learned anything, or could die after reading a few choice books. Of course, the knowledge of the land would be regulated, like medical drugs.
The two cathedrals in the Citadel stubbornly ring their bells two minutes apart, since each believes the other to be too early or too late respectively. This has been done for over two hundred years.