Bocus

Yet another text-mode variation on Tetris, where falling blocks have to be arranged and rotated to form solid rows, eliminate them and rack up score. All the familiar tetramino blocks are here, plus a smaller double square block. The speed increases every 10 lines completed, from level 0 to 9; if you feel like a challenge, you can crank up the speed yourself (though once you do, there's no way to decrease it).

As with many variants, you get to see the next piece (optionally), and some statistics showing the blocks used so far; you also get to track your high-score progress in real time, courtesy of a counter showing your current rank and the number of points remaining until the next one.