The Sunflower Virtual Gaming Table is a game engine for tabletop games focusing on single player gaming with AI opponents. It allows defining games using xml markup only, without need for programming (and in the future, might include a dedicated game creating software to make it even easier). AI opponents are created with outside plugins that may be written in a variety of programming languages.
Current version: 0.28. The first game implemented on it is Hearts – download it here.
Note that it’s an early version, might be buggy and is definitely poorly documented. Read the README.TXT file for instructions.
For full information about the engine, and for instructions and explanations about how to make your own games for it – visit the official Sunflower engine wiki.
The engine is written in Java, and released with open source under the simplified BSD license.