https://github.com/divio/classjs
Class.js is a JavaScript library for building class based object-oriented programms using JavaScript's prototypal inheritance. It strives to mimic classical class inheritance provided by other languages such as Python, Java or PHP. Its syntax is heavily inspired by MooTools's class implementation.
https://github.com/divio/classjs-plugins
Class.js plugins are aimed for professionals with extensive JavaScript knowledge. Each plugin follows a simplistic and a modular approach. All plugins have demos, tests and documentation regarding their options, methods, events and callbacks.
Distributed under the BSD LICENSE.