Avalanche is an OpenGL Tetris clone written in Java. It is still in development. Current features:
You can download the current development version here (2008-06-26).
You need the latest Java Runtime Environment (JRE). (It is the fifth item from above.)
Player 1: cursor keys, enter, backspace.
Player 2: wasd, q, 1.
Feel free to discuss avalanche on tetrisconcept.com!
Special thanks to Andre Krause for providing me with webspace and bandwidth.
Check out his blog on the upcoming game CubeStorm Planets!