A story by an author known as IllusionaryNosebleed for a reason, this story takes place in the Touhou continuity. Yukari Yakumo has planned an experiment of some sorts where she used her gap to not only bring objects from modern civilization into the world of Gensenkyou but a teenager named Ken. Ken then preceeds to not only question how he got here but his role in the entire situation as he meets several important characters and even goes through some NEGATIVE Character Development when he goes from "put on a good impression or DIE" to "Payback, bitch. Righteous justified payback". Each part of the story takes place during a different game and covers the most famous Windows games at first. It is still a WIP and has over 50 chapters. It can be found here.
Fanfic / Crossing The Border