Ni No Kuni, the studio ghibli game:
"The game will also include a book that is supposed to represent the magic book from the game and is required to play the game. In it players can find a bestiary, short stories that offer game hints and other info that the game will refer to."
I like the requiring studying a book inorder to progress, not a strategy guide, but a book that adds to the game, part of the gameplay.
See also: just about every adventure game from the '80's and '90's.
The MGS games have a ton of quirky gameplay mechanics. MGS 1 has you check the back of the jewel-case, 3 has the waiting until a boss dies, the giving a boss food poisoning so you can shoot him, etc, 4 has a dream sequence that plays exactly like an earlier game.
Gotta hand it to Kojima, he's good at thinking up quirky ideas. Mostly he just uses them once and moves on, but occasionally (Boktai) he makes an entire game around the idea.