I've just started learning about meshing, so I can make things for my Sims game, it's so much fun, except for the technical integrating part (trying to successfully put it into my game). Which is quite mentally exhausting.
Games in general, I'm always buying games, usually because I like seeing a big stack of computer games, even when my computer can't run half of them. One day I'll buy (or build) my own gaming computer and will probably never leave my room.
Wallpaper -- I love finding textures, I love wallpaper books, I love making wallpaper for my sims game, I just love wallpaper in general.
I usually browse this website for about 3 hours every day, just looking at all the lovely textures and the names and such.
Snails & Slugs. I have a tank with over a hundred snails, mostly babies, they are so fascinating to watch. I watch them for hours each evening, I love listening to them eating, they can eat half a cucumber in 24 hours, it's quite amazing. They also eat tunnels through carrots and the baby slugs use them as a cave.
I plan to make a garden soon so that I can release them into the backyard when the population increases too much. But I'm terrified of worms, so I'll have to find another way of doing it.
Aviation. Everything about it I'm obsessed with. I love the parts that make up an aeroplane, I love the sounds, I love reading about engineering and how aircraft's are made and how they function.
One day I hope to make it my occupation, even if it's just building them or building parts, since I'm sure they'll never let me fly one, hah.
I love the old war movies, especially directed by Howard Hughes, he just knew about planes, therefore knew how to direct them so beautifully.
A few others:
Science fiction, card games, space & astronomy, in fact most science, architecture and so on.
I also love crime and reading about serial killers. I have hundreds of serial killers memorized, as well as how many people they've killed and how they did it etc... Some people find it a little strange, but then you have criminal psychologists who are surrounded in that every day. I love the TV show Dexter, or at least the first season. After that they kind of butchered the series, I know the first season is based from the first book, but I'm not sure if the rest are based on the other books. The first season was mesmerizing, though, and way better than the book.