While you sleep, use your iPod device as a means to learn a foreign language or a college course or to kick a nasty habit such as smoking. We'll produce and distribute subliminal audio programs that you can play while you sleep.
All tongue-in-cheekiness aside, I think it's an idea that someone is going to pick up on and actually start developing. As with podcasting in general, none of the technology is really new as there are audio files all over the place with sleep aid sounds and behaviour modifcation themes, but you know how things go. Until someone puts a name to it, it doesn't exist.
There are currently on Google hits for 'narcopodding' (the double 'd' being the proper spelling in my opinion) and 29 hits for 'narcopoding' which all point to Chris' post. I'll bet those numbers increase exponentially over the next couple of months. You wait.