Tetris game that can be played both in a solo as well as in a multiplayer mode. Requires Java installed on the PC in order to run.
Multitris is a Java (tm) webstart game and so requires Java to play. If you don't have Java installed, don't worry. Installing it is very easy! Just go to java.com and fetch it.
Just start the game with the link above. You can play alone or with others. You can also use the online server browser to the right to auto-join new games or to look for active servers.