classyjs

// Classy //

   Classes for JavaScript

Wooya. You love JavaScript and use jQuery or another
lightweight library extensively but you notice that
your code becomes messier and messier the larger the
application grows? Well, that’s where Classy comes in.
Classy is a small JavaScript library that implements
Python inspired classes for JavaScript.

    var Animal = Class.$extend({
      __init__ : function(name, age) {
        this.name = name;
        this.age = age;
        this.health = 100;
      },
    
      die : function() {
        this.health = 0;
      },
    
      eat : function(what) {
        this.health += 5;
      }
    });

var leo = Animal("Foo", 42);
// or alternatively
var leo = new Animal("Foo", 42);

More information on the website:
-  http://classy.pocoo.org/