Readers beware; I talk about adult things here.
The one and only fanfic of Harry Potter that I ever got into apparently is gone. It's called "Like Shadows on the Winter Sky" and is by Resmiranda. It's a beautiful story which uses the intellect of the author, Resmiranda, to build up a plot; she invents her own meanings for things, builds upon arithmacy, which is the key part of witchcraft in her story, and at one describes a beautiful garden in such detail that you feel as though you are there with her characters, but aren't overwhelmed by the description.
It's a romance between Snape and Hermione, but it stays essentially non sexual. There are moments when sex enters into things, but not in the way you would normally expect from fanfics. No smut at all, thank you. Snape and Hermione never actually have intercourse, nor do they ever get on such a level as to be considered "together." Rather, he loses control at one point and goes a slight bit too far with her. The age difference is borne in mind, unlike in many other fics.
The plot is basically this: Hermione realizes that Snape is a death eater. I don't remember how. This was about two years ago that I read it. Regardless, she happens to find that out on the same night that Snape reaches the end of Voldemort's rope and rips his eyes out, using magic to ensure he'll never have eyesight again. He's put on bedrest to heal, and Hermione stumbles upon him in his room. He hadn't been in classes that day, and while patrolling (she's Head Girl), she saw his door opened and figured some brave idiots were messing around. So she investigates. What she finds is a short, quaint poem scrawled in blood on a wall.
“All day the darkness and the cold
Upon my heart have lain –
Like shadows on the winter sky,
Like frost upon the pane.”
This of course grabs her attention. To make a long story short, she finds out his situation, and Dumbledore figures "Eh, what the hell?" and makes her help Snape out with his potions to earn points for a project of hers. She's also studying arithmacy and the two of them try to use this to figure out who Voldemort will target. Arithmacy is apparently, according to Resmiranda, a way to see the future by bending math with magic. But it's like a drug, and it does terrible things to the mind if used too often--you can get stuck in false realities. So, that's the first two or three chapters of the first part of the set of two stories. They're fairly dark, but humourous rather than emo. I assure you.