The most inventive copy protection scheme I heard was in the sequel to the game Serious Sam. There are checks within the program that discover whether the game is pirated. If it discovers the game has been pirated, you'll only get so far in the game and you'll face an enemy only seen in the pirated version.... a red, invincible scorpion with two big mounted guns. 

You're not getting past that until you actually buy the game.

So that's a way of rendering a program nonfunctional without affecting users in general.