Vertris is a simple cross-platform Tetris clone written in C that uses the Allegro library for graphics. It is covered under the GNU General Public License (GPL).
To install Vetris go to the Vetris page on PlayDeb and click on the Install this now button. Enter your password and follow the on screen instructions. Once installed you can find Vetris under Apllications -> Games -> Vetris.
Install PlayDeb on Ubuntu 10.10