Have other folks experienced the same problems with their 2011 MBA that I have over just the past two weeks or so : I run a normal mix of open apps - Safari (6 or open windows - no Flash videos etc running), Excel, Airport, Mail, Sonos, Bridge Checker, Finder, Silex. I close the lid with nothing active (no file transfers or user initiated processes going on). I come back 1 hour or so later to find the fan on high (4000rpm or so) with the MBA unresponsive to any action except shut down by holding down the OFF button. MBA boots up as normal and nothing is amiss. Weird or what ! Screen saver gone mad ? I'll disable it and test again.