Somewhere between Polaroid cameras and darkroom printing lives Galaxy Hyper Speed 120. This is "roll film" of direct positive photosensitive paper for medium format cameras. I just read about it in this article on Petapixel.
What's crazy about it is, that when you process it, you get positive prints, not negatives. You can learn more about by reading the Petapixel article, then hopping over to the Galaxy Kickstarter campaign.
I think I might give this a try myself. It looks fun!