It's a new meme!!
So Microsoft has this software that you can sing to and it will generate a complete music track to go along with it.
So what do people do? Take famous songs and run the vocals through it to come up with awesome covers.
Some are actually amusingly good too.
Just search Microsoft Songsmith on youtube.
The best is, of course, Rick Astley, the metal version!
Hotel California was pretty good too:
http://ca.youtube.com/watch?v=itsT9zgWRoM