Chromecast's sonic security bypass
Chromecast, Google's streaming TV dongle, is taking a different tack by making it easier for your guests to share videos on your TV. Currently, you can cast content to the Chromecast only if both it and your device are on the same Wi-Fi network, but a future update will remove the need to share your network password.
Even cooler will be the way the Chromecast authenticates nearby devices: It'll emit a high-frequency tone inaudible to the human ear, but registered by your phone's mic. Any phones that hear the sonic squeal will be able to cast content to your TV. Whoa.