Just a simple Tasker task to toggle silent mode on or off.
I have it setup with Pebble Tasker so I don't have to dally with my phone to change the ringer settings. It replies with a notification so I am able to verify which mode was activated, though this is a bit annoying and I'll probably remove it.
This is probably not useful for a location or time based trigger which are both better handled by entry/exit events.
To install toss the file somewhere on your Android filesystem, long hold the
TASKS tab in tasker and select
Import. Oddly the menu will not show up until after you remove your finger... Then just browse to the XML file and select it.