I created a new events plugin that does the following things:

Adds an Animation API allowing you to be notified when a particular animation reaches a particular frame or when a particular animation completes.

Adds an Entity API allowing you to add, fire and remove events on entities directly

Adds an event aggregator allowing you to add, fire and remove events on any Javascript object. This aggregator is the basis for the Entity and Animation APIs and effectively decouples publishers from listeners.

This plugin can be found here: http://www.pointofimpactjs.com/plugins/view/7/impact-events