Well, I'm a HUGE Legend of Zelda peminat (it really shows doesn't it). There are a lot of other things I like, such as Hunger Games, but I don't really get into the fandom as much as I do with MLP:FiM and LoZ.
The first fandom I ever got into (online, anyway) was Codename: Kids seterusnya Door. I still Cinta it, but the fandom's much quieter now that the show's no longer in production. Another fandom I'm into is The Lion King - one that is still very active today.
I'm also into lots of games and get involved in their fandoms; Spyro, Portal and adventure games like Monkey Island being my usual ones.