I never thought I would have so much fun with this inexpensive bit of tech but wow.
It's a small dongle-like device that plugs into an unused HDMI port on your TV. Unfortunately it's not battery-powered so it also has a USB power cable.
Once plugged in, you go to the chromecast website and configure the device with a name and hook it into your wi-fi network. The devices updates itself to the latest firmware.
Then you download the Chromecast app to your Android or iOS device (phone or tablet).
Once that is complete you can download several Chromecast-supported apps (if you don't already have them) such as YouTube, VEVO, Netflix.
Then you open the app, activate the Chromecast function from within the app, find the content you want to cast or show on your TV, and hit play.
All the glorious chaos on YouTube is now on your TV. VEVO has a lot of interesting music content also. Two or more people can take turns controlling the content seamlessly from their devices.
It's a lot of fun watching the music videos for my favorite artists that were never broadcast in this country (e.g., The Durutti Column) and to see some of the highly artistic videos that accompany some of my favorite tunes.
It's also a nice way to "drive" Netflix streaming.
You can also control it or cast from any computer that uses your wi-fi via a Chromecast plugin for the Chrome browser.
It's 29 bucks at Amazon. This is yet another reason to become a couch potato but I'm fighting it by heading off to the gym right now

Jim