Perfumery.
It's something I got into a few years ago and has been a real eye-opener into the world of perfumery and our wonderful olfactory senses. Strangely, though I suspect is the case with many other hobbies, there is crossover with programming albeit somewhat abstractly.
Often it's about building abstractions and reusable components. For example let's say you wish to create an apple note (typically referred to as an accord). You're not tasked with creating the scent of an actual apple but rather the illusion of apple. This is done by mixing ingredients (usually referred to as raw materials) which are generally split into two categories, synthetic and natural, where a synthetic material if often just an isolated molecule and a natural material may be an oil extracted from nature or a tincture, among other kinds. Once you have mixed the raw materials and are happy with the result, you've essentially created a formula which is a reusable component that can then be used in one or many of your creations.
Aside from the creative process of making the actual perfume, you've then got a ton of applications in which to use it such as a fine fragrance, a candle, room spray, shower gel, shampoo, laundry detergent to name just a few.
With new raw materials becoming available all the time there are just endless possibilities as to what you can create and it, for me, has been a lot of fun both learning the craft and creating actual perfumes that I myself now wear.