Darkest Dungeon is one of the most interesting games I have ever played/witness played. It's a 2D-dungeon-crawling-roguelike. But if you're not one with video game buzzwords then essentially it's a game where you explore different dungeons and they all look different every time you enter them.
It sounds pretty standard but the difference with this game is that it has you manage and pay attention to your party's mental state. Every person has their own fears and doubts and when it's time to attack the state of their mental health might get the best of them.
Most of the time, in these kinds of RPGs anyway, your party trudges through dungeon after dungeon like it's something they've done before. When, in reality, if you were really there you'd probably be afraid of certain things like the dark or gross monsters or yucky smells of death.
Either way though, it's one of those games that adds another micro-management element that actually works. It's not something that most people think about and it's definitely engaging. There are bits where you need to relieve party members of their stress and depending on their character they might have to do it in a bunch of different ways.
One party member might want to go to church and pray while another one might want to spend a couple nights in the brothel. It's a definitely weird mechanic when you put it down on paper and sounds like something that might make the game a little more of a chore than a fun thing you do to pass the time. But in practice, it makes for one of the most engrossing RPG games you've ever played.
If you find yourself with some extra money, you should definitely pick up Darkest Dungeon. It's available now for PC/Mac.