Things have been quite chaotic around here, so I'm going to hand the microphone over to some of my respected advice-givers. Here's what some theatre directors have to say about problems directors encounter on the journey:
"If in doubt, use a megaphone or some really annoying noisy thing that will stop people talking long enough for you to say something important. It could be a bell, a whistle, or a car horn. Something so irritating that they'll stay quiet just to avoid hearing it.
"Actually, a friend of mine would regularly stand on a chair to attract attention in rehearsals and shout something completely random like "BARF!", "YOU'RE A WIZARD, HARRY!", or 'WE ARE ALL GOING TO DIE!!!".
"If that doesn't work, fake your own death and die in front of them. If anyone says you're sick just answer back that if they just stopped talking you wouldn't have to resort to such things."
-Simon Baker, on how to stop the cast for rudely talking at the wrong times at rehearsals. Hey, it happens!