If you failed to snap up a Chromecast, all is not (quite) lost: if you have an old Android device, running 2.2 or up, you can use Cheapcast to kinda sorta replicate the experience.
Designed to ape Google's dongle, it basically gives phones and tablets the ability to stream from Chromcast-friendly apps to another device on the same Wi-Fi network. So, if you have an old tablet, say, with HDMI out, you can hook it up to your TV and -- boom -- you kind of have Chromecast.
Cheapcast is available on Google Play, but it's worth noting that it doesn't really work with the Chrome browser, and, uh, it may still be a little buggy. But, hey, nothing ventured, nothing gained. [Cheapcast via AndroidCommunity via Engadget]