iOS 6 introduced Do Not Disturb, but some of us were annoyed by its implementation: Though the feature silenced iOS notification sounds while your iPhone or iPad were sleeping, those noises still blasted out when the device was in use. If that's not what you want to have happen, iOS 7 has the solution.
Armed with this hint, Do Not Disturb will empower you to use your iOS device in a room with sleeping people, or in a meeting where you're supposed to be paying attention, without fear that a bleep or bloop will bother those around you.
Head over to the Settings app, and tap on Do Not Disturb. Scroll down to the bottom of the screen, and set Silence to Always, instead of Only While iPhone Is Locked. From now on, Do Not Disturb works regardless of whether your iPhone is awake and in use, whenever the mode is enabled.
Mac OS X Hints