I know the fans are obviously supposed to come on, but I've noticed recently that if its just sitting on a desk in sleep mode, like I'll be asleep and my alarm will go off and the fans are going full bore. Or sometimes the fans will stay on for extended periods. The machine isn't hot or even warm. Right now they've been on for almost a half hour and I haven't been doing anything but browsing the web. Is this normal? I have Apple Care and its still under the original 1 year until April of this year, but is it something I should get looked at?