Earlier today, Valve announced that their Steam In-Home Streaming service would now be available starting today. Using the service allows you to stream games on Steam from a different computer in your house. Previously, the service was only available to a closed beta group.
In-Home Streaming works by running a game on your PC then streaming that on lower-end PCs such as your laptop or home theater PC, or even computers running OS X, SteamOS, or Linux operating systems. The only requirement is that both computers be running on the same network. This move is a big step for Valve to bring PC gaming to the living room and allows players to game from their couch or even lying on their bed.
For more information, you can go to the Steam streaming page.