Creating multi-screen experiences is a great way to increase engagement with applications. Google Cast lets you connect the big screen in people’s living rooms to an existing application to take advantage of Cast enabled devices like Chromecast and Android TV. Alex introduces key Cast concepts and provides a quick tour of how developers can integrate Cast capability into their applications.
https://developers.google.com/cast/ for documentation
https://github.com/googlecast/ for source code examples
https://plus.google.com/communities/115742157569103585450 for Google Cast Developer community discussions