Cuttlefish is a tool which can execute various actions when specific events are triggered, and it allows you to create events that only happen under certain circumstances
For example, you could set a condition/reaction such as “when the lan network is connected start Transmission”, or “Unmute the audio when I start Banshee and mute it when I close Banshee”.
The nice things of this program is that it’s completely configurable via a nice graphical interface that makes the creation of any task extremely easy and intuitive.
The software is wrote in python, open source and is born on Ubuntu as “Ubuntu app” and so it’s easily installable on this distribution or Derivate, there is a package from AUR for Arch Linux and I’m sure soon you’ll find it for any distribution.