Top: Kids and Teens: Games: Online: Puzzles and Mazes: Tetris (13)
http://www.simiax.com//Kids_and_Teens/Games/Online/Puzzles_and_Mazes/Tetris/index.htm

Tetris - Java based game where the pieces are moved using the keyboard.

Fibris - Online championship game in which companies compete against each other for high score. Players may add their company or play alone. Requires Shockwave.

Hextris - Java based version of Tetris where the classical pieces have been replaced with hexagonal objects.

Java Tetris - Online Tetris game with piece preview and ten different speeds. Java source code is freely available, under the GPL license.

Javascript Tetris - Has piece preview, 13 levels and background music.

MyTetris - Javascript version. Includes music and saves high score while playing.

Tetris - Includes special pieces, scoring, and a piece preview feature. Written by Steve Fu. Requires a Java compatible browser.

Tetris - Includes support for two players and nine difficulty levels. Requires a Java compatible browser. Provides sound support. Pieces are moved using the keyboard.

Tetris - Includes multiple levels, statistics on previously fallen pieces, scoring and cubes fallen count. Requires Java. Doesn't include sound support.

Tetris - Tetris game featuring daily highscore lists. Requires a Java compatible browser.

Online Tetris - Free Java game with optional sound support. Pieces are moved using the keyboard. Also provides the rules of the game.

Online Tetris - A browser based version of the game. Provides a variety of difficulty settings.

Uwan - Browser based Java versions. Also includes high scores.