Sylence is a scheduler application that will silence your phone's ringer either at a specific date and time, or on a regular interval. This is especially useful when you don't want to be disturbed while at work, in class, or even just overnight.
Simple but effective.
About the required permissions:
* "Receive Boot" is so that Sylence will start when you turn your phone on.
* "Modify Audio" is to enable/disable the ringer.
* "Wake Lock" is to enable Sylence to perform correctly and accurately; it allows Sylence to utilize the phone's processor for a few milliseconds every minute to see if the ringer should be silenced or not.
* "Internet" and "Access Network State" are for the ads and Google Analytics. You can disable the Analytics feature through the options menu.