JS Tetris is a browser based clone of one of the greatest puzzle video games of all time. JS Tetris is an open source project founded by Czarek Tomczak in 2004. To play the game you only need to enable javascript in your browser, there are no plugins required (no java, no flush). You are free to put Js Tetris on your website and to modify the game. The rules are simple: move and rotate the blocks with the aim of creating a horizontal line of blocks without gaps. Use arrows and spacebar keys to navigate blocks.
A browser version of the game is available for download. To run it, extract the zip file and open tetris.html in your browser. Download it from the Releases page.
Czarek's personal best is 332 lines, see the screenshot below.