RPTools is a brand of open-source programs designed to enhance traditional pen-and-paper role playing games. They can be used for face-to-face play, or Internet role-playing in real time even if your players are on the other side of the world. MapTool (which is our free virtual tabletop application) in particular works great with voice-chat services!
These tools are not a role playing game by themselves, nor are they meant to replace everything at the RPG table. Rather, they are designed to be as flexible as we can make them, usable for a wide variety of gaming systems, from fantasy to sci-fi; from tabletop miniatures games to purely spoken-word games.