Here is my map of lucidity. I have yet to map Nirvana. If I could find were it is.
Awake - Lucidity is being aware that your thinking, (e.g. "I am thinking.")
Going down - Awake.
Going right - Sleeping/dreaming.
Middle - Sleep paraylsis, etc.
http://img27.imageshack.us/img27/2126/mapoflucidity.jpg