There are a few ghost-town dial-up BBSes still alive and kicking, and you can connect to them using VoIP and your machine's modem. They're abandoned towns with half-finished multiplayer games, mouldering message boards, and the occassional old coot holding court:
All this makes me wonder why the Sysops who own these BBSes keep them running with such little traffic. Did they just forget to turn off their machines in 1998 as the Internet finally swept away the traditional US BBS scene? Did the old Sysops die and nobody noticed that the automated machines were still running, undetected, in a dusty back room somewhere? The possibilities are incredibly compelling; they really stir the imagination. That’s why finding such forgotten realms elicits a sense of discovery in me, like being an explorer discovering a long-lost temple in the overgrown jungles of Peru – all the more reason to give the old places a visit.
I got my start with BBSes on my Apple ][+ in 1980 or so, when we got the modem card (we'd have to take out the 80-column card to free a slot for it, so all my BBSing was in upper-case letters). I fell in love on BBSes, fought on them, got jobs through them, organized demonstrations — and played endless games. I was so hooked on Pyroto Mountain — I used to show up at the library I worked at with stacks of 3×5 cards with the mountain's trivia questions printed on them and skive off by looking up the answers on the shelves.
(Thanks, Jacques!)