HoDoKu - HoDoKu is a sudoku helper written in Java and available in English and German.
Yasminoku - Sudoku game and solver totally written in DHTML.
Math Master - Brain Quizzes - Math Master is a free math quiz game designed for all ages!
USB Sudoku - A very small program for playing the original game of Sudoku.
Less Than 8 - Less Than 8 is a fun and challenging numbers puzzle with a gameplay close to that in Sudoku.
nsudoku - A Sudoku game made with ncurses.