The PlayCanvas WebGL game engine is now open source. Access the repo on GitHub here:
https://github.com/playcanvas/engine
Read a blog article about the tech going open source on Mozilla's Hacks blog:
https://hacks.mozilla.org/2014/06/playcanvas-goes-open-source/
It's a full game engine with graphics engine, integrated physics engine (built on top of Bullet), audio, input and entity-component system.
There are some pretty cool projects that have been built on the engine. For example, check out the in-browser editor:
[attachment=22114:playcanvas_designer2.png]
Superficially, it looks a little like a streamlined version of any other visual game editor - but it's realtime collaborative (like Google Docs) and can be loaded on any device with a 'modern' web browser - Android, Chrome OS, and coming soon to iOS8. And because it's a browser app, it's always up to date with nothing to download/install.
To access the tools and community, head here:
Let us know what you think! 
