Creative writing! I mainly do scifi & fantasy (I love combining my technical background with artsy stuff). I'm currently working on a silkpunk (Ancient China setting + retro-futuristic technology based on Ancient Chinese science) science fantasy multimedia webnovel. I'm in the middle of inventing my fictional computing system (tentatively named rune engines) that ties into the magic system. I think, for a lot of science fantasy, the creators tend to keep the science and magic quite separate (ex: the science and magic of Star Wars is pretty clearly distinct) and I'm trying to create a system that combines the both of them. It's been super fun to prod at the question "how would I approach this fantastical universe using the scientific method".