When I first got the early dialup internet, I used to play telnet MUDs via DOS.
Telnet MUDs (Multi User Dungeons) were the first MMOs in a way. They were text based persistent multiplayer games. I remember one where you trained animals, others that were like adventure games, and others that were more combat oriented.
I was back then really involved with them, including being a game master (I didn’t play real D&D so I didn’t know that’s where the term came from at the time). I even vaguely remember writing content for one in something like a markup language.
MUDs still exist, and I presume DOSbox can run a telnet client…
If I missed us already doing one before I joined feel free to let me know, but if not, we should all load up telnet and jump on a current MUD together!