A few days ago, bIPlog pointed to a New Scientist article on a clever anti-piracy scheme called Fade, distributed by (of all people), Macrovision.
Fade is designed to be used with video games. The notion of it is that an illicitly-copied game will play fine at first, but gradually, Fade adjusts the game's environmental and/or control variables (like turning up the gravity, or making your player's movement sluggish) to slowly make the game unplayable.
If it works, it's extremely clever and is the kind of innovation in DRM that we need more of. Does it work? I dunno. The article's a little hazy on technology. Apparently Fade inserts "subversive" code onto the CD/DVD that looks like a scratch, which is then corrected by the CD/DVD drive's error correction. The game software, when it detects that those "corrections" have been made, begins "fading" the game experience.
More likely than not, better/different error-correction routines can be developed that will knock out Fade. Still, a gold star for effort. I once got hooked on a certain shareware solitaire game... I can't confirm it, but I sincerely believe that as I got past the end of the demo period, the hands I was dealt got worse... and worse... and worse... till I registered.