Apocalypse World is pretty much what it says on the tin - it's all post-apocalyptic. It's pretty much a pen-and-paper version of Fallout. I understand that the author hadn't actually played any of the Fallout series until really late in development, but the flavor is nonetheless right there. It has a bit of a grindhouse influence, all about guns and gore and sex and psychic mutants and whatever weird stuff you might toss in for flavor.
Generally, you play certain key individuals in a post-apocalyptic settlement - you can play a wandering band of dudes, but certain of the character archetypes focus on community. Like, if you play the hardholder, you'll literally run the town. And the hocus is basically a cult leader. This game is fairly flexible in what you can do with it, though, so long as you stay in genre. Off-the-cuff ideas:
- running a wasteland settlement, currently at fighting it out for territory with another warlord
- a group of wanderers cruising the empty interstates in a fixed up convertible, fighting off mutants and biker gangs while doing odd jobs for communities along the road
- members of a small colony of survivors in the wake of a zombie apocalypse