Fallout 4.

Ignore the main quest for the most part. It means basically nothing. Just go out into the Wasteland and do your own thing. Make settlements. Set up a supply chain. Build forts. In all the time I have in the game I think I spent maybe 10-12 hours playing the main quest once and another 500 or so just doing whatever. People complain about it not being as good as New Vegas because it isn't a Choose Your Own Adventure book in FPS form. That's because it's more of a Live Your Own Adventure GAME. The world is far more alive than any other Fallout game and it can be SERIOUSLY punishing on Survival difficulty, especially if you don't need to psychotically minmax everything. Just go out into the world and live or, more likely, die. The GOTY edition is like $10 right now.