What do your games use as currency?  Lots of AP write-ups include that info, but I haven't seen a collection of ideas.

I just had this idea for a hold/world where rolls of duct tape were the official currency and started wondering about what other stuff people came up with.

Maybe this is clear in the book and I just zoned over part of it on my read-through.  We started play with just a couple hours available and generated characters and the MC asked some questions.  And in the intervening time, we've done some fiction-building on our local forum.  And there is some concern on the part of the MC that we (players) are taking a too-active role in fiction-generation.  (I hope that's a fair way to paraphrase concerns expressed over several bits of dialog.)

So, it's the MC's job to make Apocalypse World seem real.  And to barf forth apocalyptica.  What happens when a player barfs forth?

What if I, as a player, just say that I'm going to the old air-strip to salvage old engine parts, but the air-strip has never been mentioned before and bother's someone's vision of the setting?  What if it's the MC and what if it's not?