Our last must-have Android productivity app is perhaps the most powerful and versatile of all. It's called Tasker, and it's an Android power-user's dream.
In short, Tasker lets you create intelligent automation on your device. You could have your phone automatically connect to a certain Wi-Fi network or Bluetooth device whenever you're in a particular location or change its ring behavior and volume settings based on location, time of day, or currently occurring calendar events.
I even use Tasker to route my calls to different numbers when I'm in specific places. The possibilities are practically limitless.
Tasker costs $3.