Or maybe just write Roland and Orlando snarking about them (Roland's still upset about Arthur & Merlin's popularity).
Usual fandoms: Discworld, Dr. Who, Labyrinth, Peter Pan, Song of Roland, Stargate: Atlantis, Stargate: SG-1. Asking for Harry Potter will get you a rant on why I pretend the last three books didn't happen, and Batman has too much mutually-contradictory canon for anything I write to make any difference.