I'm no insomniac, though I have a lot of trouble winding down. Some of my comments on internet groups can talk a half hour or more just to write if it ends up running for more than a few paragraphs. The upshot is that even though I intended on sleeping at about 2:00am tonight, it is now 8:00am and I still keep thinking of things to do. Even if I down the laptop and turn of the lights, I spend two or three sleepless hours thinking about all the stuff I want to be doing right about now. And for some irritating reason, I come up with my best ideas for story writing whilst lying in the dark, so I have to turn the lights on and write it down somewhere before I forget it.
My current remedy is to pull an all nighter every few days, forcing me to sleep at an early hour through sheer exhaustion, thus re-setting the whole system. Tonight will be an all nighter.