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)
https://drive.google.com/file/d/0B0ekvOGQyPytX1ZsU21oOWJ2TXM/view?usp=sharing
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.