Jundo mentioned silent illumintation the blog today. I did a google search and thought I'd post a excerpt:

Simon Child (Western Chan Fellowship)

Silent Illumination corresponds to a state, either you are in Silent Illumination experiencing the Principle or you are not. If you are actually in Silent Illumination you are no longer Practicing - you are in the state. What is it like to be in that state? The name gives a clue Ė Silence and Illumination. Even so one could fall into the trap of thinking there are two things here. Actually these are two aspects of the same state. Silence means the fussing mind (memories, fears, wants etc) is silent. Itís not that you donít hear. You do hear the birds singing. If you tune them out you donít have Illumination. With Silence and Illumination your mind is clear and reflecting what is there, not lost in a trance.

http://www.westernchanfellowship.org/si ... ion-1.html
Shikantaza wikipedia article: