Mysticales: Old Populous did that with the manual. Some even made you type in a word from a page. Great game still. =)
And still others actually made the copy protection part of the "immersion" factor of the game. For instance,
Space Quest V had you enter the coordinates of the planets you traveled to that were only to be found in the game manual. Yes, it's easily memorized, copied down, or otherwise relatively easily defeated, but it
did make sense within the context of the game -- and looking up coordinates from a galactic map added an additional layer of verisimilitude.that wouldn't have existed with more traditional (and code-munching) DRM.