Speedcube - A simple and elegant Rubik's cube solve timer
NullpoMino - NullpoMino is an open-source action puzzle game that works on the Java platform.
Linia - You will never look at colors the same way...
Blockinger - An open source Tetris clone for Android.
Colorcube - Turn pieces and blend colors in this minimal puzzler
Good Old Tetris - Play Tetris Online. The game that will never get old.