This logs every time an event is fired. It gives good insight into how ckeditor starts up and operates. The events and params show up in Firebug's console.log. Just FYI.
diff --git a/ckeditor/_source/core/event.js b/ckeditor/_source/core/event.js
index 8668a3d..d974444 100644
--- a/ckeditor/_source/core/event.js
+++ b/ckeditor/_source/core/event.js
@@ -216,6 +216,7 @@ if ( !CKEDITOR.event )
return function( eventName, data, editor )
{
+if(console && console.log) console.log((editor ? editor.name : 'CK') + ' fired ' + eventName + ': ', data)
// Get the event entry.
var event = getPrivate( this )[ eventName ];

Re: how to watch fired events
Re: how to watch fired events
open _source/core/event.js
find
return function( eventName, data, editor ) {and below it add:
Make sure you are pointing to ckeditor_source.js or you recompile