I posted this last month: http://www.beesource.com/forums/showthread.php?t=217910
My mom's bees were attacking people several yards away from their hives, and when I went in to look at them they were overly aggressive. We knew they had been queenless but we had seen a mating flight go out from the hive. After that mating flight they started acting weird. We concluded that something happened to the queen on her mating flight, putting the hive in a "hopelessly queenless" state. We put in a frame of young brood, and they settled right down! We'll see what kind of queen we get, mom's tired of their aggression.