After years of rumours we are finally getting an announcement from Valve regarding Steam in the living room as Valve have just announced SteamOS. The new OS from Valve will soon be available to download completely free. The OS will feature in-home sharing which essentially allows you to stream your games from your PC running Steam to your TV with a computer running SteamOS and will also include support for the recently announced Family sharing ability. The OS will also support media features as well with valve looking bring media services directly to the OS.
More info is said to become available with the download being available soon. In the meantime check out the source link below for information.
Source: Steampowered.com