Silencer is an OS X app that lets you set a schedule for the muting and unmuting of your Mac’s audio.
If you’re the type to leave your Mac on overnight, then you might have experienced waking up in the middle of the night by an unexpected sound.
Silencer allows you to schedule muting and unmuting using a very simple interface; you simply enter the time you want your Mac to mute and unmute the speakers and Silencer will take care of the rest. Silencer runs in the menu bar next to your clock.
You can purchase Silencer from the App Store for $0.99.