External annunciator for Mac?

I have Skype, and am using it quite a bit right now. I’d like to have some sort of flashing external ringer outside my computer that would sound and light up when a Skype call comes in and Skype puts an announcement on my screen. I want this to happen even if the screensaver is on and I’m away from the computer.

Does such a thing exist on the Mac? Would it use USB? Can Skype trigger actions/Applescript/whatever when a call comes in? Thanks!