Lucid

Lu"cid, a. [L. lucidus, fr. lux, lucis, light. See Light, n.]
1. Shining; bright; resplendent; as, the lucid orbs of heaven.

Bright with the radiance of intellect; not darkened or confused by delirium or madness; marked by the regular operations of reason; as, a lucid interval.

Syn: Luminous; bright; clear; transparent; sane; reasonable.

Lucid Dreaming?

Lucid dreaming is when one can regain consciousness in a dream state.  Enabling them to control their dream in any way, shape, or form.  I'm not sure quite how its done but its very interesting.  Suppose I'll just have to research it one of these days