My taste for the last several years is to play around with
1: dedicated industrial logic (e.g. elevator and machine controllers)
2: Analog computers
3: Electromechanical stuff, especially if somewhat programmable
Now, none of the above are things with video screens and
keyboards, and in most cases they don't even have readily
recognized "instruction sets", but they all do computing in a
pre-Von-Neumann sense.
I heavily, heavily try to stay away from stuff with keyboards
and video screens and, even worse, anything with an
"operating system" of any sort! I don't want to have anything
to do with installing software. I want to solder tube sockets,
read meters, turn knobs, and watch scope traces.
Tim.