From Tetris Online:
Tetris Friends Online Games is the official social gaming destination for the world's most popular puzzle game, Tetris. Play a variety of Tetris games including multiplayer games, single-player games, and nostalgic games you've played before. Earn tokens as you play games and unlock enhancements and items. Customize your avatar and compete in local and global leaderboards. Play free online games at Tetris Friends Online Games.