I recently install #linuxmint ( #linux) on the relatively new laptop of my SO, and after that (really totally frictionless) experience and the enthusiastic reaction to the new system, I am going to try and slip this to relatives as "Windows XE (Extra Edition)" and see whether I ever get caught out.
(My father has been using Linux for years now, installed by my brother-in-law and still hasn't gotten aware of it ...)
People, out there, don't let anybody tell you that "Linux is not mature for the desktop". It's just not preinstalled.