Social Canvas is probably the world's largest multiplayer game installation. It functions like most tile-matching video games except on a much, much larger scale.
Visitors to MGM Cotai can quickly join the game by scanning a QR code and submit entries by sending messages to a dedicated WeChat channel.
These entries are then displayed in “The Spectacle”, MGM’s term for the world’s largest area of permanent indoor LED screens that makes up their lobby and casino entrance.
MGM's write up is here. The featured videos show an overview of the project and a demo of the project in action.