Emitter.js

//grab the Event Emitter from the events module
var Emitter = require('events');

//create our own instance of an Emitter
var emtr = new Emitter();

//create a new event and response on our listener
emtr.on('greet', function() {
  console.log('A greeting occurred!');
});

//emit an event manually 
emtr.emit('greet');

//emtr, which was listening to a 'greet' event responds with
// 'A greeting occurred!'