Plot Hinge is a serial novel project in which the outcome of real-world events decide how weekly chapters unfold. At the end of each chapter the plot is left at a cliff hanger with the story able to go in a couple different directions.
I then tell the readers something like: "If it's a cloudy night in Toronto next Tuesday, then the guards won't spot Jimmy trying to escape. If it's a clear night, Jimmy will be spotted and brought back to prison." The following week's chapter is then written based on the outcome of that event.
So while it's a fictional story, the plot hinges on these real-world events outside our control. The prologue to the story is live now with the outcome of Groundhog Day determining how Chapter 1 unfolds. Weekly chapters begin Feb 2nd.
You can read the prologue entitled "Will's Worries" right here, and you can check out tons more about the project and the history of serial novels at the Plot Hinge site.