I used to work for Lotus Support in the UK in '93 - '94 and we used to play games over the office network once we knocked off for the day. First with NetWars (https://en.wikipedia.org/wiki/NetWars) and then Doom. When you shot a colleague with a rocket launcher for the first time....

//EDIT// We also used to connect to a Lotus FTP server in the US so we could download new WADs that people had built.