Wow, a lot of folks with very technical backgrounds ! And a surprising amount of Aviation people too !!
I've been an Aircraft Maintenance technician for the last 20 years. All heavy commercial transport stuff (737,767,747, A320 & A340 ). In my younger days in the Army reserve I played at being a Vehicle Technician.
My hobbies lately involve my lathe and milling machine that I've been teaching myself how to use...... mostly for gunsmithing stuff etc.