1. I suppose you could say that I have 3 special interests. They are all interconnected.
2. Anime - I've been obsessed with this since I was 7, and although I have taken breaks from it, I always go back to it. I indulge in it by watching episodes (typically 2 - 5 per day), drawing anime-style, using avatars/icons/wallpapers/Facebook cover photos of my favorite anime characters, listening to the soundtracks from my favorite series, daydreaming about my favorite characters and wearing T-shirts representing my favorite series. Basically everything short of writing fanfiction, doing cosplay and going to cons.
Crossover pairings - I've been obsessed with this concept since the age of about 13 or 14. It's where you take 2 (or more if you're into polyamory) characters from different movies/books/TV shows/anime/games/etc, etc. and pair them off romantically in fanart, fanfiction, fan vids, or image manips. I used to feel excited when I found artwork/fanfiction of the same pairings that I enjoyed, but these days I get far more enjoyment out of coming up with my own pairings and hoping that I'm the one who starts a trend! I also enjoy seeing other people creating and supporting crossover pairings even if the characters involved aren't from an anime, or even if they aren't from a fandom that I am even remotely interested in. I just really, really like the concept of crossover pairings.
Anyway, I indulge in my crossover pairing obsession by making lists of my favorite pairings, lurking on Deviantart for artwork depicting crossover pairings, doing manips of my favorite crossover pairings, and making artwork depicting my favorite crossover pairings. I'd love to write fanfiction for my favorite pairings, but unfortunately I don't have the confidence or patience for it.
Imaginary friends - I've been obsessed with this concept since the age of 5, which is when I got my first imaginary friend. This obsession mostly revolves around the act of acquiring and interacting with my own imaginary friends, as it is a difficult topic to research since very little information is available about this phenomenon and very few people talk about it in blogs or forums. All of my imaginary friends come from works of fiction since I have never been able to come up with my own. The way I indulge in this obsession is by getting my favorite fictional characters to become my imaginary friends (can sometimes be harder than it sounds), talking to my imaginary friends, listening to music that reminds me of my imaginary friends, pretending that my imaginary friends follow me everywhere and comment about what I'm doing, lurking on Deviantart for pictures that people have drawn of their imaginary friends, and scouring the web for any information I can find about imaginary friends.
3. Indulging in any and all of these obsessions makes me feel euphoric, energetic, excited and restless. I agree with the earlier poster who said that special interests are better than sex. I couldn't have put it better myself. 