I figured, to exercise creativity, I made up a pretty simple game, or whatever passes as a game. So, here's the rules:
One person comments a very vague story idea. The first person to reply gets to build up on that idea.
EX: The first comment says something like...I dunno..."A romance involving rivals," and the second person can build off of that. Maybe they say why they were rivals, or maybe they turn the plot into some enemies-to-lovers thing. That's just an example, make up whatever you want.
This can continue until at least there's a basic idea of how the plot goes.