I just thought this might be something interresting to share...

I've been planning on doing this for a long time now and two days ago I got my chance: to meditate in my sleep.
Here's what happened...

I was having something of a nightmare (more like an attack by annoying beings in a dream). Throughout the dream there was a man who was trying to kidnap me.
There came a point when this particular agressor attacked by lunging at me. At that point I simply decided to sit/'float' down (in the half-lotus position, just as I do in real life) and close my eyes. Immediately I felt the effect of a good five minute's worth of meditation.

All went silent and grey, and then turned to white as I 'let my mind go' without thought, feeling or 'sound'. When I opened my eyes again my agressor dissipated like a gas into the air.

Shortly after that my alarm clock woke me up.
Unfortunatelty conquering my exam-demons at school wasn't so easy though... =p

Anyways, it's definetly an idea I recommend for anyone who meditates. =)