EZDM (ezdungeonmaster) is a simple set of tools for dungeon managers, targeting AD&D 2nd edition rules. It's not an RPG game, but some helper tools for people DM-ing real games, and is designed not to get in the way of roleplay and storytelling, but simply help do the math during encounters and leveling. Dice rolling can be done by the computer, or the tools can be set for manual dice, in which case you simply enter the results of the roll. All game data, charts, and character sheets are stored in JSON format. The EZDM kit defaults to using a simple dialog-based GUI which requires easygui, but a console interface is also available.
Vallheru is a turn-based, fantasy MMORPG written in PHP and MySQL (but may work with many other databases) with Smarty Template Engine, ADOdb, and PHP Mailer. It is based on Gamers-Fusion 2.5 with many modifications in security, speed, and features. It is currently available only in Polish.
HLA Adventure is an adventure game that was written in Randy Hyde's HLA language. It features Mippy, a cute dragon that lives happily in the forests and caves and often comes out during the later part of the day to eat leaves, smoulder decaying trees, and generally romp around like every good dragon should.
Marauroa is a multiplayer online game framework server. It uses a multithreaded server architecture with a TCP oriented network protocol, a MySQL based persistence engine, and a flexible game system. The game system is totally expandable and modifiable by game developers and is able to run Python scripts defining the game's rules. Marauroa is based on a design philosophy called Action/Perception. Marauroa is totally game agnostic and makes very little assumptions about what are you trying to do, allowing a great freedom to create any game type.
Proelia is a multi-game system encounter tracker for pen-and-paper RPGs. It allows you to create "prepared" encounters for later use, and then run them any number of times with the click of a button. A group can be created from an encounter's participants, and then re-used in other encounters. Each encounter can display a map that allows you to track positioning of participants, especially in relation to regions, so you can tell if someone is standing too close to a fire, or is subject to an aura or other environmental effect. A color and marker text can be set for each participant in the encounter, so you can quickly find them on the map. A variety of RPGs are supported through a plugin system that allows new systems to be added.
roll is a command-line program that rolls a user-defined dice sequence and displays the result. The die are defined using dN, where N is the number of sides. They can be rolled multiple times by prepending the number of repetitions (e.g., 3d6) and used in simple mathematical expressions (e.g., 2d8+4).