Via musesfool:
Maggie Fitzgerald and the Saltwater Drip, a long (80,000 words) COMPLETELY AMAZING Spiderman AU where it's Gwen Stacey rather than Peter Parker that gets bit by the radioactive spider, and that changes everything. I'm not the hugest Spiderman fan, but this story is seriously what fanfiction exists for: to look at how a small change in canon can have amazing and wonderful consequences. The characterizations are terrific, the plot is gripping, and the exploration of the gender and racial dimensions of Gwen as Spiderman are really compelling. It builds mostly on "Amazing Spiderman" canon, but also has comic characters like MJ and Miles Morales. Really the best story I've read in a long time.
This entry is crossposted at
http://norwich36.dreamwidth.org/258562.html, but feel free to reply at either place.