Google Chromecast is a nice hdmi dongle which you can connect to the tv and use it to stream all kinds of things from your phone, tablet and computer.
It is now from December that I have one, and I can say I am very pleased with it.
How does it work
The setup is pretty straightforward: you just need to connect to the tv, follows the screen instructions, and you are off to the races!
The dongle is controlled from your phone, and there are several apps that do interface with it directly, from example Netflix and Youtube.
The interesting bit is that your phone is controlling the dongle, like a remote control, however is not a screen share. Therefore you can use the phone at the same time you are streaming to the tv. This is a massive battery saver and gives you the ability to read the odd email if you need to, without interrupting the streaming.
Using google-chrome, and installing an extension for google chromecast, you have also the possibility to share any tab on the tv directly, which is very handy if you are looking at an embedded video.
Last but not least it is possible to share pictures and videos on the tv, a feature I used in a bunch of occasions.
TL;DR
I honestly think it’s a good value for money, and if you are watching youtube or netflix and you want an easy way to move it to the tv, the Google Chromecast is what you want.