Tetris in your browser. Visit it once and it works offline (if your browser supports service workers) so go ahead and add it to your home screen.
It sounds like a gimmick but there's something very cool about this. In Soviet Russia, keyboard rotates you!
An iPhone game that mashes up Sudoku with Tetris. "Drop numbered discs into the grid. Whenever the number on a disc matches the amount of discs in its row or column it disappears. Keep the board open to keep scoring, and survive as long as you can. Clear the board or set off huge chains for big bonus points."
A decent version of Tetris written using jQuery.
Very very cool and addictive cross between Tetris and geography knowledge. It took me 19:45 to get all of Europe on a medium setting. That's pathetic.