Do Not Disturb feature
Here, Forstall also showed off iOS 6's new Do Not Disturb feature. When it's turned on, your iOS device will still receive push notifications, calls, and text messages, but they won’t light up your screen or make a sound. For added control, you can allow certain numbers to sound your phone as they otherwise would even when Do Not Disturb is enabled. If someone calls you back within three minutes after a muted call arrives—implying it’s urgent—your phone will ring.