Dwarf Fortress [official site] has been generating fascinating anecdotes for years, but those stories have been told by its players. Soon the dwarves themselves will join in: recent posts to the game's development log have dealt with adding the ability for your fortress inhabitants to write their own stories, poems and alternate histories.
What makes this different from the existing ability for dwarves to depict events from their lives in, for example, wall carvings, is that books can travel and communicate ideas. "Philosophical study opens up different avenues of discussion that allow people to pass their values to both individual readers and to a lesser extent through the underlying civilization when there's a library with a copy." This includes the very style of prose the book is written in, as certain poetic forms might be created and passed between regions, but can also or will also eventually extend to the ethics of your community.
I'm unsure what affect they'll have upon the world, but the alternate histories sound especially fun. The examples given in the most recent update include "dwarves wondering what life would be like if an antelope man hadn't attacked their town," and one historian who "wrote a book considering how things would have been if the author had remained an architect instead of becoming a historian a decade before." I wonder every day where I'd be if I hadn't spent all those childhood years playing on the Amiga.
Although all of this is now in the game, it's not yet in the publicly available build. Developer Tarn Adams tends to write about new features regularly but release those as updates far more occasionally. Still, the update is below in full and makes good reading as always:
The work on adventurer composition led into finalizing the new written content generally and making sure I had handled all of the promises I'd made to various people over the last few months. Philosophical study opens up different avenues of discussion that allow people to pass their values to both individual readers and to a lesser extent through the underlying civilization when there's a library with a copy. This doesn't impact specific ethics yet, so you won't have to worry that an elf-written book will make all your dwarves start eating dead bodies, but such a thing is now threatened for a later date by these changes. Poetry written in certain poetic forms can currently spread values before philosophers come up with specific language that can be used in prose, though not all civilizations will have such traditions.
Generally, there's more information in all of the written content now, and there are more sorts. For instance, after the difficult concept of an alternate history is tackled by historians, they can write books pivoting around the negation of particular events. Mostly it hasn't been earth-shaking... dwarves wondering what life would be like if an antelope man hadn't attacked their town or if a competition had turned out a different way. One historian wrote a book considering how things would have been if the author had remained an architect instead of becoming a historian a decade before. It would be possible to weight the event selected with an importance check, but there are complications as usual. There are also cultural histories, genealogies, atlases, chronicles, the various biographies I mentioned before, etc., which have their proper topics and sometimes some historical events selected, and they occasionally push a value agenda when the author and form is capable of it.