Playing together has always being one of my favourite parts of gaming. That's probably I like board games and roleplaying so much.
Early digital games had the tight playing together feeling. Sharing the keyboard or just playing in turn with the same computer / console was the way to go. In extremes it was a group of friends playing the same game, one controlling the game while others giving instructions and tips in the background.
The culmination of playing together on a single device was this castle building game which name I have since forgotten. I just remember four of us trying to squeeze close enough to be able to share the keyboard (wasd and arrow keys), mouse and joystick around the table and trying to see our part of the playing field on the small 14 inch crt monitor.
The first "network" games were played on two computers connected with the zero-modem cable. Setting that up was not trivial and probably one of the things that had contributed substantially to my problem solving and debugging skills.
It didn't take too long to move from those directly connected machines into a true network. Via the so called "fat" ethernet with coaxial cables and terminators finally to somewhat modern "thin" ethernet.
Back in the days it was an event in itself to gather together with our computers and setup the network . Sure there are lan parties today as well. But with this always connected world those aren't so special anymore.