Journey to the West
Elements of the story have been ripped off so many times for other IPs, and there have been a few games loosely based on the book, but they've been tactical RPGs, and platformers, and the like. What Journey to the West needs is a 3D action-adventure game where you play as Monkey and beat the crap out demons with your gold-banded cudgel. Like a (literally) linear Zelda, you'd travel the road, find cities and caves with quests to help people and kill bad guys, but since Monkey already has tons of abilities, there'd be a lot more freedom in taking on any situation.
Monkey himself is a great character with lots of cool powers like transforming into various animals and things, flying 1000s of miles in seconds, making many clones of himself. And he does lots of cool stuff like beating up the kings of hell so they'll erase his name from the book of death, fighting against all the lords of heaven, having a mountain put on top of him for 500 years (not so cool for him), fighting tons of monsters and demons, and generally going from place to place with his companions getting into the maximum amount of trouble, while almost always being a total unstoppable badass.
The episodic nature of the book would translate extremely well into a game. Everyone should read the book, but a well-made game would exposed more of the western audience to the Chinese classic.