I love mechenical things and cycling, so what better things to experiment with than bikes. Vintage bikes are also very approachable, repairable and unbreakable, which makes them great to work with! I love customizing bikes for different purposes. Some just to restore to the beautiful machine they once were, others to be fitted with modern parts as a stylish daily driver.
Customizing/building and designing my own tools for music creation is great. I'm at the front line of shaping the tones and getting the best feel out of a guitar that I could possibly want.
Same as vintage bikes, vintage amplifiers are fairly easy to work on. They are often hand made, which also makes them repairable by hand. Getting a broken (guitar) amplifier is like a mystery package. Fixing and breaking down what is exacly wrong is a great project to wrap your head around. And the beautiful sounds you can make after is a great reward.