Smooth asynchronous user interfaces for iOS apps — AsyncDisplayKit (Permalink)

Facebook open-sourced their AsyncDisplayKit:

AsyncDisplayKit is an iOS framework that keeps even the most complex user interfaces smooth and responsive. It was originally built to make Facebook's Paper possible, and goes hand-in-hand withpop's physics-based animations — but it's just as powerful with UIKit Dynamics and conventional app designs.

They've mentioned this multiple times before in their tech talks on Paper, I'm glad it's finally out.