Late on Friday, December 13, Valve released the first public version of SteamOS. As you would expect, SteamOS is currently very rough around the edges -- it is essentially just a version of Debian 7.1 ...
If you have an old Windows laptop gathering dust, there are plenty of creative ways to make it useful again. You could turn it into a second monitor, repurpose it as a file server, or even convert it ...