Linux &The Planet Games: viTetris is a terminal-based Tetris clone.

viTetris is a terminal-based Tetris clone by Victor Nilsson. Gameplay is much like the early Tetris games by Nintendo.
Features include:

Configurable keys
Highscore table
Two-player mode with garbage
Network play
Joystick (gamepad) support on Linux or with Allegro

It has been tested on Linux, NetBSD and a few other Unix-like systems, and ported to Windows and DOS. Library dependencies are minimal (only libc is required), and many features can be disabled at compile-time.
Version 0.50 can run in graphics mode using the Allegro library, but blocks are still "drawn" as characters with an 8x16 console font.

Source Code

To compile vitetris you need a Unix-like environment with a C compiler and other basic development tools.

vitetris-0.57.tar.gz
Installation instructions: INSTALL
vitet055src.zip for DOS
Installation instructions: INSTALL.DOS

Binaries

Linux:
vitetris-0.55-i486-linux.tar.gz
Built with gcc 3.4.6 for i486-linux on Slackware 11.0.

Linux Packages

Gentoo: ebuild-vitetris-0.57.tar.bz2
Packaged by matt the guy. Unpack into $PORTDIR_OVERLAY (in /etc/make.conf, often set to /usr/local/portage).
Then type "emerge vitetris" and you're done.

Screenshots.