Learning while you sleep

Hypnopedia: Learning in your sleep.
I came across this in a forum devoted to learning Mandarin. While I'm skeptical that it's functionality is practical, I can't help but wish that it works.

It reminds me of an episode of "Dexter's Lab" where Dexter falls alseep while attempting to learn French. The record skips and keeps playing "omelett du frumage" over and over. When he wakes up in the morning, all he is able to say is "cheese omelet".

Unfortunately, the results of testing of Hypnopedia seem to be counterproductive. I guess you mind needs that quite time to form memories. *sigh* Maybe I could recover sleeping time through multiphasic sleeping instead. That would be nice.