Android: One of the best features of Android is how finely you can tweak notification settings. An XDA developer created Ringer to provide a stack of new customisation options for your phone's ringer.
The app can perform run-of-the-mill tasks such as silencing your phone when it's face down, or controlling ringer volume. However, it also has some impressive advanced functions such as automatically setting your phone to silent mode whenever an event from your calendar is active. The app isn't available on the Play Store yet, but can be downloaded for free on XDA.