I was thinking about this question earlier today and wondering how, exactly, I should answer this. One the one hand, I am still immersed in pretty much every CLAMP fandom that I have ever joined. But, finally, I settled on this answer…
Cardcaptor Sakura
Besides being something like the spiritual precursor to Tsubasa (and giving me my third favorite CLAMP guy) it is also the series that I'm most actively involved in at the moment. I am currently two thirds of the way through the anime and starting to think about buying the manga. As I'm typing this, I also have a Cardcaptor Sakura wallpaper in the works.
While this is not even close to my favorite CLAMP show, it is much more fun than I ever expected. It has also surprised me in the level of maturity that this show approaches things with. While it has a fourth grader as the main character, it is certainly no kiddy show.
I pretty much adore all the characters and have enjoyed the fun little romp that this show is.
I will not be on the internet over the weekend, so I will pick my challenge back up on Monday.
