Open Meridian

Meridian 59 was among the first, of the the first, 3D online mmorpg. Originally released 1996, it is still playable, but now in the form of a Free version called Open Meridian. Based on the original data-files, but with an open engine, the project allows playing the "Meridian 59: Community Edition" - A complete modern version of the classic game. The page describes the game as having a lot less "holding hands" compared to modern mmorpg:s, and there seem to be skills to build, guilds to join and players to ally or anger. Certainly something different if you're looking for a new online RPG to play!

Not exactly modern, but it doesn't look bad by any means.