Jetris is an Open Source Cross Platform JAVA 5 Tetris Game Clone
JETRIS is ...
A Java based Tetris clone. It can be played online as Java applet or as a standalone desktop game. Jetris is focused on a fast gaming, so a game usually takes about 15 min. You can post your HiScore online.
System requirements
JETRIS is written in JAVA programming language, this means that it can be run on any Operating System which has JAVA Runtime Environment (JRE). You need JRE 1.5.0 (also know as JRE 5) or above.
Macintosh OS X 10.4 Tiger or Later, or Windows. or Linux
http://jetris.sourceforge.net/