##Option 1: Using jQuery 1.7's $.Callbacks() feature:

var topics = {};
jQuery.Topic = function( id ) {
	var callbacks,
		method,
		topic = id && topics[ id ];
	if ( !topic ) {
		callbacks = jQuery.Callbacks();
		topic = {
			publish: callbacks.fire,
			subscribe: callbacks.add,
			unsubscribe: callbacks.remove
		};
		if ( id ) {
			topics[ id ] = topic;
		}
	}
	return topic;
};

Usage:

// Subscribers
$.Topic( 'mailArrived' ).subscribe( fn1 );
$.Topic( 'mailArrived' ).subscribe( fn2 );
$.Topic( 'mailSent' ).subscribe( fn1 );
// Publisher
$.Topic( 'mailArrived' ).publish( 'hello world!' );
$.Topic( 'mailSent' ).publish( 'woo! mail!' );
//  Here, 'hello world!' gets pushed to fn1 and fn2
//  when the 'mailArrived' notification is published
//  with 'woo! mail!' also being pushed to fn1 when
//  the 'mailSent' notification is published.
/*
output:
hello world!
fn2 says: hello world!
woo! mail!
*/

##Option 2: Using .on() and .off():

Ben Alman's really tiny pub/sub with my 1.7 updates from https://gist.github.com/1319216. The link to his gist with lots of useful comments is here: https://gist.github.com/661855

/* jQuery Tiny Pub/Sub - v0.7 - 10/27/2011
 * http://benalman.com/
 * Copyright (c) 2011 "Cowboy" Ben Alman; Licensed MIT, GPL */

(function($) {

  var o = $({});

  $.subscribe = function() {
    o.on.apply(o, arguments);
  };

  $.unsubscribe = function() {
    o.off.apply(o, arguments);
  };

  $.publish = function() {
    o.trigger.apply(o, arguments);
  };

}(jQuery));

Usage

// Super-basic example:

function handle(e, a, b, c) {
  // `e` is the event object, you probably don't care about it.
  console.log(a + b + c);
};

$.subscribe("/some/topic", handle);

$.publish("/some/topic", [ "a", "b", "c" ]);
// logs: abc

$.unsubscribe("/some/topic", handle); // Unsubscribe just this handler

// Or:

$.subscribe("/some/topic", function(e, a, b, c) {
  console.log(a + b + c);
});

$.publish("/some/topic", [ "a", "b", "c" ]);
// logs: abc
// Unsubscribe all handlers for this topic
$.unsubscribe("/some/topic"); 

##Option 3: Using the jQuery UI $.observables

Demo: http://jsfiddle.net/jUZmM/ Implem: http://view.jqueryui.com/grid/ui/jquery.ui.observable.js More information: http://wiki.jqueryui.com/w/page/47179578/Observable

/*$.observers/$.observables example by @addyosmani*/

The basic idea behind observables are that when objects/collections of data
are changed or updated, events often need to be triggered to inform any 
observers of the change. This is a concept you see in a few different 
frameworks (Backbone's Collections for example);

// The array I would like observed
var myData = [];

// An observer instance of my array, that can be observed
var observer = $.observer(myData); 

function dataChange( data ){
   console.log('New data arrived with ID ' + data[0].id + ' and value ' + data[0].title);   
}

// Bind a callback to be executed when the data
$(observer).bind("change", function ( e ) { 
    dataChange( e.target.data );
});

$.observable( myData ).insert({
                id: myData.length + 1,
                title: 'test'
            });