You can download it and then install it in a partition on your hard drive or even better on a USB stick and keep it separate and try it out if you feel the curiosity. Comes with it's own built in applications allowing you to surf the internet watch movies etc and their own app downloader as Google do not allows licensed vendors.
So paid applications from the Playstore / Amazon would not work but third party APK's would.
It can be interesting to try as you do not have to uninstall the operating system you have and if you just want to use certain applications on a bigger screen for example. Just read about it so have not tried it myself but have the urge and will go out and get a new USB stick and try it out and see how well it performs with some music applications.
To read more go here:
This video will explain it in more detail and it shows how easy it is and that it is totally separate if you want from your computer environment.