Organizations: Ministry of Magic | Order of the Phoenix | Death Eaters

Sports: Quidditch

The Wizarding World: Animals & Creatures | Magical Objects | Patroni/Animagi | Horcruxes | Wands | "The Rules" | Wizards vs. Muggles | Death

More summaries:
Characters | Places | Wizarding World | Books 1-7 | Jo |
Interviews of other people "in the know"