Over at the doom9 forums they are discussing the program Fairuse4WM program that strips any media file that plays on Microsoft's Windows Media Player. This includes Zune Marketplace Downloads, Walmart Downloads, Amazon UnBox, BBC iPlayer files and even your local library file downloads.
Why would you want to do this? The reason I would do this is to be able to listen to the music I purchase from a player specific platform on a non-supported player. I don't share the music and you shouldn't either. Once The content sellers and the music/video companies free all tracks from DRM, this of course won't be necessary.
EDIT: Dave Zatz has confirmed that this does work on video files. He tested it out on three weeds episodes purchased from Amazon Unbox.
I haven't tried this out, but others are saying it works. You can do the same sort of thing with iTunes files as I mentioned back in June of this year.
via doom9 forums