Eastgate Systems http://www.eastgate.com
has three important works of literature that depend on hypercard:
Uncle Buddy's Funhouse <http://www.eastgate.com/catalog/Funhouse.html> emulates a writer's computer with hypercard stacks of passwords, reverse worlds, and mysteries.
Marble Springs <http://www.eastgate.com/catalog/MarbleSprings.html> explores a nineteenth century Colorado gold rush town. Graveyards, jails, and churches reveal and conceal the connections in this elaborate history.
Intergrams <http://www.eastgate.com/catalog/q11.html> Complex experimental poetry where every move of the mouse discloses new phrases and combinations.
These still work in OS 10 in hypercard. Can we really lose these works of literature to a dying software?