I'm not sure whether or not this is a very short one-shot or the beginning of a Hogwarts Years Marauder story from Sirius' POV. I'll see.
Sirius Black and the mystery of the Whomping Willow By: Lakritze A Black always goes to Slytherin, especially the heir. But the Sorting Hat put Sirius Black in Gryffindor, where he has to deal with the blood traitor James Potter, the shy Peter Pettigrew and the Half-Blood Remus Lupin. Original: /s/6989729/1/Sirius-Black-und-das-Geheimnis-der-Peits
Based on a prompt in the HP Forums: Whilst tidying his room, Ron stumbles across something rather odd that he decides to experiment with. Chaos ensues. What did Ron really think when he met Harry Potter for the first time? Read to find out!