well there's alot of old school MMORPGs out there run by fans using emulators and pretty decently powered servers
Ultima Online by UOGamers is one of them
The Lineage series is always extremely popular with america and china/japan/korea
there's DoTA which is an RTS style MMO game
and League of Legends which would take the average player 2 weeks to figure out.
Im waaay out of the mmo loop ever since I moved from jersey and haven't had my own net, but these are just a few.
In all honestly though you should look into Dwarf Fortress. It's like this shitty looking DOS game thats so immensely deep you'll be finding out stuff about it for years after you started playing. Never played it myself, but have heard some things. anyway why did i type all this, it's back to chugging beer and being a faggot for me