The folks behind Duet Display have released a Windows client, allowing you to extend your machine to any iOS device.
Plugging in a second monitor to extend your computer from one display to two is just about as far from a new concept as you can get, but taking an existing piece of technology and using it as a second monitor temporarily is something of a challenge. Duet Display was the first app to make an iOS device into a 60fps second monitor with touch input for OSX, and it remains one of the best experiences for temporarily extending your desktop setup when you're on the go.
Until today, this experience was limited to Mac users with iOS devices. With Windows support now available, Duet Display can now be used to extend the desktop of just about every computer on the planet. We've been using Duet for Windows for a couple of days now, and while it's not yet perfect the experience is thoroughly enjoyable.