Thomas Ness has documented some interesting thoughts and methods on interfacing the Processing language with the Skype API. In doing so, this allows notifications to be received from Skype and acted upon by other code. A fascinating by-product of this relationship is Processing and Arduino. Therefore with Thomas' theory one could create devices that take action once a message or call is received by Skype. From his page you can download the appropriate code and libraries, and an Arduino example is also included.