NullpoMino - NullpoMino is an open-source action puzzle game that works on the Java platform.
Tetris on a plane - Simple, open-source HTML/JS/CSS version of Tetris built as an exercise.
Tetris Blitz - Race against the clock in a two-minute blitz to clear lines and rack up points before time runs out.
Blockinger - An open source Tetris clone for Android.
Cuyo - An open source Tetris-style puzzle game for up to two players.
1010! Klooni - 1010! Klooni is the FLOSS version of the original minimalistic puzzle game by Gram Games.