Microsoft Garage Mouse Without Borders allows you to control up to four computers from a single mouse and keyboard. Beta version also available.
This ability means that you can quickly copy text or drag n' drop files across multiple computers.
Mouse Without Borders was originally a Microsoft Garage project authored by Truong Do. These Garage projects are considered to be side projects that Microsoft employees, like Truong, build just for fun on their nights and weekends. Mouse Without Borders was designed with those people who need to use many computers in the same room in mind. A good example of this is, for instance, a laptop or tablet that you bring to meetings can sit right alongside the desktop PC in your office.