Build Your Own Apocalypse

From the itch.io page:
Build Your Own Apocalypse
Build Your Own Apocalypse is a GM-less collaborative storytelling game. You decide on the setting. You decide on the characters involved, if any. The story is mainly about the events that bring about the decline and destruction of your setting. The characters you make up won't be able to stop it, but you could tell a story about the villains that make it happen. Build Your Own Apocalypse makes a great lead in for many post-apocalypse games with a mysterious precursor.

The rules for Build Your Own Apocalypse are two pages long. Game play with four people takes 2-3 hours. The game is infinitely re-playable and can be played with children capable of imagination and rolling dice.