I came home a couple of nights ago and walked into a darkened room to see that my iBook's screen was illuminated while the case was shut. I figured that somehow the machine must have woken and crashed, which really never happens but wouldn't be too far out of the ordinary. I looked away for a second (before doing anything to the machine) and my iBook was sleeping - that was strange indeed. About five seconds later I saw the screen turn on again, and I knew something was wrong. I opened my iBook and all seemed normal, but every time I put it to sleep it was have fits of insomnia. I rebooted. Then I reset the PMU. None of this did the trick. After googling in vain for anything relevant, I came to the realization that my keyboard had popped up ever so slightly! I reseated it, pushed the tab in and put my iBook to sleep without incident. I really don't know how the keyboard came up, but I assume I was stupidly fiddling with the tab.
So here's the upshot. I'm wondering how much premature age I've put on my iBook's precious hard drive by having it spin up and down every five seconds or so for a whopping
five hours! 
Even though I've been able to rationalize that laptop drives are designed to be spun up a great amount, I'm still quite upset at myself and a bit worried about the whole thing.