I'm picturing a ttRPG about a post apocalyptic world that got to that point because someone found that a part of the structure of property deeds in a key country had never actually been tested in court, and someone decided to do so, resulting in complete chaos as no property rights were legally enforceable anymore and gridlocked government couldn't agree on a fix. And with that country in chaos the dominoes started falling elsewhere. (It feels like a nice change from the ones that happen because of nuclear war or disease or huge climate change... but I'm not sure how exciting it would be without cyborgs, mutants, zombies or whatnot).