Firefox OS, codenamed 'Boot 2 Gecko' is a fully web-based open mobile OS by Mozilla that will take on the smartphone market.
  
Having Linux underneath, Firefox OS will support everything you would expect from a smartphone including HTML5 apps written using 'open Web' technologies rather than platform-specific native APIs.
Firefox OS daily builds are now available for desktop. Installing them is very easy, just follow the instructions below:
 
Download latest Firefox OS build from here.

Extract it to get a b2g folder.

Run the following commands to install Gaia and make a new profile:

  • git clone git://github.com/mozilla-b2g/gaia
  • make -C gaia profile
Now to run Firefox OS, execute:

  • /path/to/your/b2gfolder/b2g -profile gaia/profile

These builds are experimental meant only for developers, so don't judge them yet. here are some screenshots