OCTGN

OCTGN is a Card Game engine for playing card games online. It's an application for MS-Windows and run on .Net4.

Anyone can create a game definition file (A mix of xml and python) which will define the various rules of the game and any scripts to automate various play. Players then import the various set of the card game and create decks to play. It varies from most other online card game engines, such as LackeyCCG by its support for scripting, which allows each game plugin's author to automate various tedious tasks to speed up the game or avoid player mistakes.

The latest release of OCTGN is 3 and it now has a built-in lobby functionality and is being actively maintained by a new development team. The old version (2) is still available but defunct.

One can find available games and sets in the OCTGN Game Directory