A super simple and easy to use Bus.

AppBus.js

//The Bus module:
//========================
var makeBus = function () {

    var subscribers = {};
    var subscriptions = [];

    var makeDeliveryJob = function (client) {
        return function (event) {
            client.Receive(event);
        };
    };

    var makeSubscription = function (subscriber, eventName) {
        var subscription = {
            Subscriber: subscriber,
            EventName: eventName,
            Send: makeDeliveryJob(subscriber.Client)
        };
        subscriptions.push(subscription);
        return subscription;
    };

    var makeSubscriber = function (client) {
        var subscriber = {
            Client: client
        };
        subscribers[subscriber] = true;
        return subscriber;
    };

    var subscribe = function (client) {
        if (!event.hasOwnProperty("Receive") && typeof client.Receive != 'function') {
            throw "Interactivity Failure: " +
                "Tried to subscribe a subscriber object missing a 'Receive(argEvent)' function. " +
                "Add a 'Receive(argEvent)' function on the subscriber before subscribing.";
        }
        var subscribeTo = function (eventName) {
            var subscriber = makeSubscriber(client);
            makeSubscription(subscriber, eventName);
        };
        var to = function (eventName) {
            subscribeTo(eventName);
        };
        return {
            To: to
        };
    };

    var sendSubscriptions = function(event){
        for (var i = 0; i < subscriptions.length; i++) {
            var subscription = subscriptions[i];
            if (subscription.EventName = event.Name) {
                subscription.Send(event);
            }
        }
    };

    var publish = function (event) {
        if (!event.hasOwnProperty("Name")) {
            throw "Interactivity Failure: " +
                "Tried to publish an event object missing a 'Name' property. " +
                "Set a 'Name' property on the event object before publishing."
        }
        sendSubscriptions(event);
    };

    return {
        Subscribe: subscribe,
        Publish: publish
    }

};

//Usage:
//=========================

//The bus object
var bus = makeBus();

//Build a subscriber
var someSubscriber = {
    Receive:function(event){
        //Handle the event here.
        window.alert(event.Data);
    }
};

//Build a publisher
var makeSomePublisher = function(){

    //Build an Event
    var makeSomeEvent = function(eventData){
        return {
            Name:"SomeEvent",
            Data: eventData //Add this or as many other properties as you like!
        };
    };

    var publishSomeEvent = function(){
        var someData = "xyz"; //Events can have interesting data!
        var event = makeSomeEvent(someData);
        bus.Publish(event);
    };

    var doSomeStuff = function(){
        //Do your thing here!
        //When you're done, publish an event!
        publishSomeEvent(eventData);
    };

    return {
        DoSomeStuff:doSomeStuff
    };

};
var somePublisher = makeSomePublisher();

//Interconnections for the win!
bus.Subscribe(someSubscriber).To("SomeEvent");
somePublisher.DoSomeStuff();