Illusive sleep, where for art thou?

I sure wish I knew why sleep is so illusive some nights? I know all the things that can keep sleep at bay, and avoid them. Caffiene, naps, ect. Its never about that. Like last night for example. I was so tired, but then my legs got itchy, and my body got restless. I felt like running around outside to ease the discomfort. Perhaps the neighbors would have called 911 if I HAD done that. Try to explain why you are outside in the nude, at 1am. Try to explain why you are running around like a mad woman, screaming, SLEEP, SLEEP!!!!Some nights I sleep like days of old. Dreams and everything. Oh How I long for those nights when sleep doesn't come. Maybe because our time on earth has a limit, we are not supposed to sleep as much. Maybe we ARE supposed to run around outside in the nude.[ Preferrably after dark] Late ta....