K2W RPG
A collection of open source client, server, and editor you can use to build and run your own online RPG.

DimensioneX Multiplayer Adventure Development Kit
Offers a freeware Java software capable of building and running multiplayer adventure games, playable with any browser. Several multiplayer games are available for free as a demo.

Orion CRPG Game Suite
Create and play Dungeons and Dragons style text adventures for Windows.

Exult
Version of Ultima VII for Unix, Windows, Mac, BeOS.

Faldon
Online role playing game for Windows with equipment, items, magic, skills, levels, experience, and a real-time battle system.

Lost Hero
A classic-style Java-based game, with information and download.

Umbra
Free humanity in a randomly-generated world. (Requires Python)

Progress Quest
Players build their character from a ninety-pound level one teenager, to a warrior, well able to snuff out the lives of a barnload of bugbears without need of so much as a lunch break. (Windows)

Dungeon Game
3D dungeon crawler for Windows or Linux.

IRE
User-editable clone of Ultima 6 for DOS, Windows, BeOS, or Linux. (Open Source, BSD)

Dark Ages II
Medieval DOS game in which the hero must defeat a wizard and avenge his family's death.

Tibia
Medieval fantasy online game for Windows or Linux full of exciting adventures, mighty magic, and great battles.

Hadinshu
Provides information, media, guides, and development information on Hadinshu, a fan game similar to Final Fantasy.

Wheel Of Time - Light And Shadow
An online virtual community in Java based on Robert Jordan's Wheel of Time books. [Open Source, GPL]

Zelda Classic
Replica for Windows of NES version of The Legend of Zelda. Includes development notes, download, enemy list, walkthroughs, and FAQ.

Palace of the Tragic Prince
Provides a download of the game called "Heart of Steel", information, screenshots, and links.

Crisis Wolverine
Provides a download of "Crisis Wolverine". Includes information, news, and media.

Fanwor
Describes Fantastic World style game for Atari and Linux, with download.