I've always been fascinated by the idea of humanity's survival on a galactic time scale. How will we survive in a hundred thousand years, in a million, billion, etc.
So I'm making a game based on that. I was already thinking about something along these lines before the theme was announced, so it was a pretty happy coincidence. Humanity leaves Earth and tries to survive in the solar system, in multiple solar systems, in multiple galaxies etc. As you move further away from Earth you move further in time to different epochs, as entropy breaks down potential resources and it becomes more and more difficult to survive.
The game uses a sheet of graph paper to mark the human diaspora's journey, as well as a standard deck of playing cards. The cards represent different things (hearts are people, diamonds are food and fuel, clubs are ideas and culture, spades are technology like weapons and tools) and the players use them to move the human diaspora, overcome challenges, and role play scenes that occur during each turn. Each player has a playbook that represents one of the guilds in charge of the operations of the diaspora which give them special abilities based on their suit. For example The Spades guild is better at addressing challenges with spades cards, etc.
So it's basically a GMless role playing map game about humanity's survival over the next trillion years. Right now I've got the basic rules, a rough draft of the map, and I'm making the playbooks so I can start testing the game.