Purplest Prose is a group writing game wherein you slowly auto-generate (and frantically try to make narrative cohesion out of) trashy romance novels.
It's a really fun concept, and it works great as a party game for writers.
Again, it *is* about writing the synopsis for a trashy romance, so probably be on the same page as everyone else before you play it, but it'll throw things at you like "write a formula harlequin about a samurai and an office worker who meet during their class reunion", and now you're stuck trying to come up with nonsensical over-the-top innuendo that fits that situation.
I think I'd recommend this to anyone that writes, that likes trashy novels, and that has friends who do the same.
For folks that are not necessarily interested in the trashy novels bit, the game formula is also really easy to adapt, so you could make it about formula pulp, or cookbooks, or anything else with a bit of homebrewing.