Dood : The Puzzle Planet - A strategy puzzle game for the smart ones
NullpoMino - NullpoMino is an open-source action puzzle game that works on the Java platform.
PH Builds a Puzzle - A realtime, collaborative jigsaw puzzle.
Blockinger - An open source Tetris clone for Android.
Atomas - Simple rules, endless fun!
Good Old Tetris - Play Tetris Online. The game that will never get old.