I have one of the new ibooks and I've been leaving it on 24/7 for the past couple of days, just closing it when not in use (I assumed this put it to sleep, no?) Today as it sat on a pile of phone books the fan came on a few times. I was eating dinner, so I didn't look at it right away, but when I did it was pretty hot to the touch and wouldn't wake up. I hit the space bar, tried the track pad, and ctrl + apple + del, and heard the hd spin, but nothing happened. Finally I pressed the power button and it restarted. This isn't the first time that this has happened. Twice while using itunes I plugged in my ipod but couldn't figure out how to get it to import updated songs, so I put the machine to sleep throught the apple menu, and couldn't wake it up without restarting. Now that it's up and running again everything works fine, but I'm worried this is a bad sign. Please help!