It was the best of times, it was the w... nope. Just the best.
zonklezoop
Back in the olden times, before the WWW came along and the internet exploded, you'd fire up your modem and dial into other computers. Bulletin Board Systems.
They would typically host some local forums, files to download, private messaging, and some online games. Larger ones might have a chat room. As time went on, networked forums got popular. Mostly text interfaces, but ANSI graphics and menus were common.
It was really the best.
Setting one up to be accessible via telnet is a fun little project. Install a couple of doors (games) like Legend of the Red Dragon, Pimp Wars, Usurper and just have fun.
You could run a BBS! Synchronet and Enigma both have Docker images available.
It's really the epitome of a pointless endeavor, but it also gives you an entirely new kind of system to learn, tinker with, and customize.
Oh good, they came up with a stupid new term for something that people know, understand, has been around for well over 50 years.