I found this online ages ago (probably around the mid-2010s -- maybe 2017) but long ago lost the tab, title, or any identifying info and searching has been no help.
The basic outline of the story went something like this: some philosophy grad students are living in an attic in a fantasy city. Being philosophy grad students, they are struggling to pay the rent. Late one night of drinking, they hit on a great idea--they'll found their own religion to make money tax-free! They quickly draw up some divinely inspired sacred texts, decide who gets to play the prophet/disciple/bishop/martyr/etc roles, and pick a nearby street corner to arrange some "miracles" on.
It goes all too well for them--they get plenty of money to pay the rent with, but suddenly the whole thing becomes a huge hit all across the land, people start converting in droves, the government turns hostile, fights break out about doctrine and dogma and ritual...and some of the students who made up the whole thing start sincerely believing in it as well. There are schisms and crusades and inquisitions and stuff--I can't remember how it ended (or didn't get that far) but things get way out of hand.
Anyway, I know it's a long shot, but if anyone has any leads I would love to find this story again, thanks!