Fandoms?

I'm sure you all know of my abiding love for Firefly? Indeed I think it would be hard to miss :) And due to my icon posts and actual participation on the comms, I think my Magnificent7 flisters know I'm interested in that. But what other fandoms do we have in common? Old ones we don't talk about much anymore? Ones we think no-one else is interested in? Fandoms we lurk around, but never comment in? (I'm bad at that) Do you read the fan fic? Keep up with the news? Here's my partial list...I'd love to know yours. ( total geekdom ahead )

And this leads to my final question - How come I write/read fan fiction for some shows and not others?