Framer

I recently got pretty jazzed on the Facebook prototyping tool Origami for sketching out animations and interactions for iOS but quickly deflated once I realized that the learning curve was steep. Fortunately, I was clued in to FramerJS just yesterday and am now equally excited at the prospect of being able to prototype apps simply from a PSD without Quartz Composer, Flash, or any of their ilk. I've not immersed myself in it yet but the recommendations I've received and the examples are enough to keep it in the Exciting Potential realm for me.