The game Tetris which I wrote for a CMPE160 project.
If you just want to play it, here's a (Windows) runnable version of the game. (It includes the .jar file inside. You can run it on Mac and Linux, too)
Extract the .zip file and start kstetrisstarter.bat
You can add more backgrounds to the game. Just add your images (preferably 200x400) to the assets/background folder with names like "background#.png". You can change assets as you like, too.