Building objects the IIFE way

gistfile1.js

var Speaker = (function () { 
  function Hello() {
  } 

  Hello.prototype.repeatAfterMe = function (message) {
    return message || 'fine, be that way';
  }; 

  return Hello;
}());

var a = new Speaker();

a.repeatAfterMe('hi'); // 'hi'
a.repeatAfterMe(); // 'fine, be that way'