NVIDIA has issued a new beta version of its GeForce Experience tool, you can download it over here. New in this release is beta support for GameStream Co-Op, a feature that lets you and a friend play together cooperatively over the Internet just as if he/she is sitting right next to you. More details and a game compatibility list can be found at this page.
This release also brings a cool new feature called GameStream Co-op that lets you stream your game over the Internet to a friend and play together cooperatively – just as if your friend was sitting in the chair next to you. Using Gamestream Co-op, you can now get help on a tough level, play in co-op mode, or just do a real-time 1:1 live stream with your friend. It's fast, fun, and a whole new way to enjoy PC games.