Devices that move: bicycles; motorcycles; cars; et al. I like to work on them and I like to use them. I have mostly "vintage" stuff, though my wife's Miata somehow turned out to be one of the few with factory tuned suspension, LSD, and the other homologated goodies.
I owned a automotive repair shop for a couple of decades until I sold it, so I have seen the good, the bad and the ugly. In my twenties and thirties, I worked at a dealership where I earned BMW Certified Master Technician status -- first on motorcycles, then automobiles.
Currently, I have a slew of old bicycles, a few motorcycles (R100RS/MS, V7Sport and V50 Monza Guzzis), and about a dozen old cars (Alfa Giuliettas, a Toyota TE38, a '61 Rambler convertible, a '30 Model A, a '15 Model T Speedster and some trucks, as well as a 2000TI and a retched 2000CS).
I am somewhat cursed with property maintenance responsibilities, so I also try to enjoy carpentry and plumbing, in addition to being a pretend electrician.