Kyle Reese has traveled backwards in time, not to save Sarah Connor, but to help her rewrite the faulty utility function of Skynet. Together, it's possible that they might avert Judgment Day and save the world from nuclear Armageddon - and hopefully create a utopia ruled over by an AI god in the process.
Recursive fanfic of Harry Potter and the Methods of Rationality by Eliezer Yudkowsky. Fits in around chapter 94, and contains major spoilers. Harry Potter starts to come around to the idea that souls might exist.
The year is 1934, and Superman has arrived in Metropolis. Features Lex Luthor as the villain protagonist as he comes to grips with the arrival of an alien god. Occasional point-of-view chapters/sections featuring Lois Lane. Takes place outside any established comics continuity.