A fascinating fantasy world which draws heavily from anime influences, classic fantasy of all varieties, and of course is just a thing all its own. I have been lucky enough to campaign through Uresia with its creator, and every turn is a detailed, researched, and deliberate funny/sad/terrifying surprise. Not only is Uresia: Grave of Heaven packed full of world, but it invites the players, readers, and fans of all types to add their own twists in its friendly and inclusive online community! You won't be disappointed by Uresia, so check it out!
Also see Risus: The Anything RPG! Uresia is system agnostic, but it lends itself so well to Risus for me.