1.js

MyApp = {};
MyApp.vent = _.extend({}, Backbone.Events);

MyApp.vent.on("some:event", function(){
  alert("some event was fired!");
});

MyApp.vent.trigger("some:event");

2.js

MyApp = new Backbone.Marionette.Application();

MyApp.vent.on("some:event", function(){
  alert("some event was fired!");
});

MyApp.vent.trigger("some:event");

3.js

MyApp = new Backbone.Marionette.Application();

MyApp.UserManagement = (function(Backbone){
  var mgmt = {};
  var mgmtEvents = new Backbone.Marionette.EventAggregator();

  mgmt.UserListView = Backbone.View.extend({
    events: {
      "click .user": "userClicked"
    },

    userClicked: function(){
      var user = // get the user that was clicked
      mgmtEvents.trigger("user:selected", user);
    },

    // ...
  });

  mgmt.UserDetailView = Backbone.View.extend({
    // ...
  });

  mgmtEvents.on("user:selected", function(user){
    var view = new mgmt.UserDetailView({
      model: user
    });
    view.render();
    $("#detail").html(view.el);
  });

  return mgmt;
})(Backbone);

4.js

MyApp.vent.on("myChannel", "myEvent", function(){
  // do stuff here
});

MyApp.vent.trigger("myChannel", "myEvent");

5.js

MyApp.myChannel = _.extend({}, Backbone.Events);
MyApp.anotherChannel = _.extend({}, Backbone.Events);

MyApp.myChannel.on("someEvent", function(){
  // ...
});

MyApp.myChannel.on("anotherEvent", function(){
  // ...
});

6.js

MyApp.vent.on("some:namespaced:event", function(){
  // ...
});

MyApp.vent.trigger("some:namespaced:event");