Also I aint filling sis Lilith's schedule with OP but am trying to do it with Gintama instead. :p Gintama requires a little knwoledge of most mainstream anime titles as it is a comedy show and parodies shows like death note, one piece, naruto, bleach and even itself lol. There was an arc parodying mario, nintendo wii and traditional rpg games and one parodying dragon quest. :p
either way, not recommeded for those that havent seen a specific bit of most mainstream titles. YOU NEED TO WATCH IT SOMEDAY THO. It is the best anime ever. Yes, even better than OP in my eyes. OP manga is still at the top for me, though.