Everyone loves to download emulators and ROMs for all the old SNES classics, even PS1 games are available on some sites now. What about MUDs? I found muds around Ultima Online peak because I needed a free game alternative. MUDs were like early MMORPGs, basically text-based games that have some visual representations to make playing easier. Achaea is a good example of a mud thats been running since 1997. Alot of muds have shut down over the years because they're simply not as popular anymore, but the overall mud demographic is in the thousands, if you add up the playerbase from all the muds @TopMudSites.
MUDs are alot more fun if you've got a friend to play with, or enjoy roleplaying and communicating with other players. Like with any MMO, its alot more fun to level through the newbie areas with a partner. The first MUD I ever played, called Age of the Throne, is sadly defunct now, but it had a great newbie experience. A player would be matched up with you and it was their job to show you the ropes, and the mentor-player earned some game gold for guiding you around. The live player guide has been replaced with tutorial windows, so MMOs have really lost the social aspect of roleplay that MUDs provided. I mean honestly, if you're really looking for an awesome social + roleplay experience, where players work together to advance game storylines, MUDs like Achaea are really where its at. A few other MUDs worth mentioning are Aetolia, Imperian, Midkemia Online, and Lusternia.