Oh man, I have quite a few:
Drawing- Would come naturally, since I'm doing A-level course in art, and aspire to be an animator. Pretty much solely cartoon characters, fanart, that kinda stuff.
Animating- Mostly stop-motion and pixelation (animating inanimate objects), but I'm thinking about trying out hand-drawn animation. Only problem is the startup costs are monstrous. You need the cels, the backgrounds, the drawing boards, x-sheets, lightboxes, the cameras, the software, etc etc.
Ninjutsu- I go to a weekly class, where they mainly teach the combat half, rather than the strategy or the lifestyle. But it's fine, because I got a tonn of books on the subject of Ninjutsu, and they all have sections on strategy. I'm a big ninja enthusiast, but I only hold a 9th kyu greenbelt in the art, which is equivalent to a yellow belt.
Warhammer- Currently collect a chaos daemons 40k army. I'm mostly into the collecting, modelling and painting, but I can hold my own in battle. Plus, chaos daemons are just so interesting, in that they have an exception to pretty much every basic rule of the game.
Roleplaying- Mostly live-action variety. I run a small group of foamfighters (Combat games, using foam-rubber weapons of our own construction), using the Dagorhir system. I hope that once I'm 18, we can apply to become an official chapter.
Dr Steel's Toy Soldier Army- I am a proud soldier in the army, and a big fan of the doc's work, be it his propaganda, his message, or his kick-ass music (sort of a blend of jazz, folk, rap and industrial metal). I'm off to my first invasion tomorrow, in fact!
I'm also into alot of occult stuff, but I won't go into too much detail, lest I incite an overly intense debate.
Oh, and I self-teach myself drumming. You can check out an example on my Youtube channel.