What is Do Not Disturb on the iOS 6 update?
Apple has added Do Not Disturb to the iOS 6 update, which makes it easy to guarantee your iPhone doesn't interrupt you at the wrong time. When Do Not Disturb is enabled, the iPhone will be silent and the screen will not light up for alerts.
You can manually switch on Do Not Disturb anytime by navigating to Settings -> Do Not Disturb -> ON.
To set Do Not Disturb to automatically engage every day, use Settings -> Notifications -> Do Not Disturb. Here you can turn Scheduled -> ON and enter times for automatic silence. You can also customize Do Not Disturb mode to allow calls from certain contacts, or to allow 2 calls within 3 minutes from the same person to come through in case of emergency.