Google's not making any hardware itself, but Sony, Sharp, and TPVision will all start shipping TV's that run with Android TV software in the fall, and Asus, LG, and a few others will also be releasing set-top boxes that will run it, too.
You'll also be able to use voice search to easily find content. For example, if you say "Breaking Bad" into your phone, Android TV will call up the television series, but also info about the cast, YouTube clips, and related search terms. If you click on an acress in the show, you'll then be offered a bunch of other shows and movies that that person is featured in. Because of Google's Knowledge Graph, you can also make more complex searches, like "Oscar nominated movies from 2002" and ask questions like, "Who plays Katniss in "The Hunger Games?"
Another big focus of Android TV was gaming. You'll be able to play some your favorite game apps on your TV -developers will get the developers kit today and the Android TV app store will open in the fall.
You can also play multi-player games, like NBA Jam, featured above, to play against your friends. Players can use their Android phones or tablets as controllers. Generally, you'll also be able to interact with Android TV using one of Google's new smartwatches.
Android TV will also have full support with Google Cast, which means that it will be integrate with Chromecast, Google's TV streaming dongle. Google also announced a few updates for Chromecast. For example, you'll soon be able to let your friends beam content to your TV with Chromecast without using the same Wi-Fi network you use, and set your own photos as the background on your TV when you're not watching anything.
This is actually Google's second attempt to create TV software: Google TV which launched in 2010, flopped.