One of the few things that stuck in my mind from William Goldmans book about the year that he was both a Cannes and Miss America judge, was how concerned that he and many of the other judges were about staying awake at screenings, particularly on the first jet lagged day.  Appearently judge George Miller (the MAD MAX and medical one) suggested chewing gum as a device that would keep you from nodding off.  Goldman said that it worked too.