Mouse without borders is the best app ever created. It's a tiny little program that lets you share a single mouse and keyboard across multiple workstations over a network.
It also shares clipboards and files across the connected machines.
Now I have it hooked up to my desktop, my laptop, and my Surface. I have visual studio and the browser containing the app on the main 30" screen, documentation and outlook on the laptop, and the New York Times and youtube on the surface :-). And can control them (almost) seamlessly as if they were one - save for moving windows in between them obviously!
Everyone who has more than one windows device needs this.