Key apps: Google Play, Netflix, and YouTube
It's truly impressive that a device this tiny has the potential to be as powerful as it is. About as big as a USB thumb drive, the Chromecast plugs into your TV's HDMI port (and draws power from a wall adapter or USB port) and then connects to Wi-Fi. After that's done, you can use Chromecast to send content from your computer, tablet, smartphone, or other device to your TV. Begin streaming Netflix on your iPad and you can move it to the TV. Ditto for a YouTube video you're watching in Chrome on your laptop. (Chromecast also enables you to display your web browser on the TV, but that's less relevant here.) The gadget works only with apps that support it, so it's fairly limited right now, but expect a lot more app support, such as Pandora and Hulu, to arrive soon.
Pros: Great price; cool PC/TV integration; easily portable to other TVs.
Cons: Few apps currently support it; no included remote; requires HDMI port.