When a Brave wanted to have a vision he would go up into the hills and deprive himself of sleep. Putting rocks between his toes and using other methods to induce pain, he would keep himself up for days until the gods would talk to him, showing him images of the future, the paths he should take, and enlightenment.
This modern day warrior experiences sleep-deprived hallucinations on a monthly basis thanks to jetlag and the general inability to sleep on planes. I stay up for 30 or more hours regularly. It is an interesting experience, for at first there is a period of intense sleepiness and fatigue, making the ability to think straight nearly impossible. Then on the other side of that thoughts start arranging themselves again, but in a pattern I am unable to control. Creativity flows on its own as ideas pour forth from my mind. Blog entries, novel outlines, symphony compositions all rush forth at a speed I am unable to write down. I tell myself I will remember them all and write them down later, but I never do.
When sleep finally overtakes me, the ideas leave, the muse goes away, and all I am left with the vague idea that I had some pretty good ideas that I can’t quite remember.