One of the great things about sharing a world that you're creating with others is that the way others interact with it, the characters they want to be in it, and the kind of things they suggest putting in (either directly or by way of asking questions,) it can really help energize your creative process.
The World I Am Currently Building
In my game Undeadwood the player characters start as people who have been transported on a mysterious Phantom train crewed by demonic entities to a pocket dimension called Wonkatonkwa.
The characters arrive in 1869 with no memory of anything that's happened since 1867. To them, the Civil War is over and the grudges were starting to smooth over, a new host of opportunities were opening, and Manifest Destiny is at its high point in American Consciousness.
During character generation, they can find themselves in possession of strange objects. One of the Pin my test group started the game with $16, and a photograph of a recently assassinated politician from the north with an X-drawn across it.
Wonkatonkwa is a haunted country. Hoodoo magic, Santeria, Alchemy, and Pow-wow rites all work. At night, the spectral forms of people who have died in the desert rise up to drain the life out of the living so that they can once again experience the pleasures of being a living being themselves. The Devil himself hangs out had a crossroad in the eastern part of the county. And creatures from American folklore like hodags, the wampus, and the snallygaster plague the people who have no choice but to make a life there.
