PyTaTo is a free virtual tabletop written in Python and Pygame designed for playing classic pen-and-paper games on a computer, over a network.
PyTaTo offers an entire environment for playing and managing games from tabletop role-playing games to Tic-Tac-Toe.
PyTaTo has a chat window for group chat, a drawing window to help with visual representation of the game, and a shared documents system to make synchronized data easy to manage.
Not only that, because it`s written in Python, PyTaTo is relatively easy to extend the environment with custom widgets, making it possible to build a client optimized for a particular game.