Post Script is a mod for Half-Life 2 which is kind of like Fallout, only without the mutants. The Road, only without a whiny kid. I Am Legend, without vampires. You get the idea.
It's a five-part game that is more "episodic narrative" than shooter. In fact, it doesn't look like you shoot anything, ever. There are some puzzles to solve, but mostly, you're exploring what's left of a small town after the end of the world, digging through the remains to learn what happened in the final days before the apocalypse.
As someone who spent more time digging through empty fridges in Fallout 3 than he probably should have, it's right up my alley. Episode 1 is available now, and you can grab it here, while you can check out some trailers and screens at the game's site below.