Microsoft just announced that later this year you'll be able to stream Xbox One games to any Windows 10 device in your house. Which is freaking nuts.
Generally, Microsoft made it clear that its intention is to turn Windows 10 into a gaming platform as much as Xbox One is. Besides what we're seeing today, we're going to get a lot more information about Windows 10 gaming at the Game Developers Conference in March.
First of all, let's be clear: The streaming will only work within your house. Attach the two devices to your local network and then "Set up a relationship" between them so that they're paired. Then when you're on you PC or tablet, you fire up the Xbox app, click "Stream from your Xbox One" and poof, like magic you're playing Forza.