> In the past, I used PARnet to connect two Amiga computers via the parallel port.
That is very cool! Not Amiga but Linux: back when I was still on dialup my 486 desktop PC had a PLIP (Parallel Line IP) connection to my crappy laptop and so my brother and I could both be using the Internet at the same time. The laptop was so old and underpowered that it'd just be running a X11 server and the 486 desktop would be running the graphical session (including the browser) shown on the laptop.
IIRC the cable was just a regular parallel cable (the same kind we'd be using back then for printers).
It also felt like magic back then: one computer running two browsers, with one displayed locally and the other remotely over a parallel cable... All the while monopolizing mom's landline for the dial-up connection!