Someone went mucking about with a timeturner, and Harry is the only one who notices the rather drastic changes. More or less ignores HBP.

Voldemort stumbles across an ancient spell that will change Harry's life forever. Set during OOTP and diverges pretty sharply from there. May use some elements of HBP.

AU: Harry learns that the wizarding world has its own Christmas traditions that he gets swept up in.