6k+ Harry Potter and the Natural 20 » by Sir Poley Milo, a genre-savvy D&D Wizard and Adventurer Extraordinaire is forced to attend Hogwarts, and soon finds himself plunged into a new adventure of magic, mad old Wizards, metagaming, misunderstandings, and munchkinry. Updates monthly.
Harry Potter & Dungeons and Dragons, T, English, chapters: 74, words: 314k+, favs: 7k+, follows: 8k+, updated: 8/2/2018 published: 5/7/2012
10k+ Harry Potter and the Methods of Rationality » by Less Wrong Petunia married a biochemist, and Harry grew up reading science and science fiction. Then came the Hogwarts letter, and a world of intriguing new possibilities to exploit. And new friends, like Hermione Granger, and Professor McGonagall, and Professor Quirrell... COMPLETE.
Harry Potter, T, English, Drama & Humor, chapters: 122, words: 661k+, favs: 27k+, follows: 20k+, updated: 3/14/2015 published: 2/28/2010, Harry P., Hermione G.