PokerWorld:
Here is an example of a project I created.  It is a non-betting poker game based on the GridWorld framework.  Every poker player is a world and the scoreboard is also a world.
Click here to see a Sample Project Proposal for PokerWorld.
Click here to download the Executable File for PokerWorld. Save the zipped files to a folder, simply navigate to the folder and double-click on the PokerWorld.exe file to run the game. 
Click here to download the Java Classes for PokerWorld.
 
PokerWorld