So it has happened to me twice in the past couple days. A couple days ago i left my MBP on and also had it open over night. When it is idle for a certain amount of time the computer will go to sleep, which it did, but the problem occurred when i tried to wake it up the next morning as it would not wake up. I had to instead hold down the power button until the computer turned off, and then turned it back on again. It started up fine except i got the error report saying something along the lines of "Your computer had to be restarted after Mac OS X quit unexpectedly" and asked if i wanted to report this problem to apple (which i did). I wouldn't think much of it but, this exact thing happened again later that day. Does anybody know why this happened? Has anybody else had this problem? I am running Leopard OS X 10.5.1 so i was thinking that it may just be some kind of bug in Leopard, although i have been running leopard pretty much since it came out and haven't had this happen until now.