Along with a new Nexus 7, Google today announced Chromcast, a $35 HDMI dongle that connects to your home Wi-Fi network. When attached to a TV and network (and separate USB power), other computers, tablets, and phones on that network will be able to see it and "send" video to that TV. Desktop apps, mobile apps, and web services--independent of operating system--will be able to throw video to the Chrome-running Chromecast dongle, such as streams from YouTube and Netflix. Chromecast will actually just receive the streaming address of that feed and not the actual video feed itself, so your laptop or tablet doesn't have to maintain a connection during streaming. Music streaming is also supported, as will entire webpages from browser tabs.
Chromecast is available for pre-order now, and will be shipping August 2nd. It also comes with a 3-month Netflix subscription, effectively making the Chromecast a $12 buy for existing Netflix subscribers. Here's Google's video advertisement showing off how Chromecast works: