Popcorn.js is an Open Source (MIT Licensed) JavaScript library (with no dependencies) maintained and hosted by the Mozilla Foundation but involving professors and students from Seneca College's CDOT. Contributions are also made by Bocoup in Boston.
Popcorn folklore and legend : There used to be a web-based Popcorn builder where you could specify the plugins you wanted to include and it would build a special version just for you. Apparently now you can build your own using https://github.com/cadecairos/JS-Builder. You'll need to deploy a copy of it yourself on Heroku though.