JigSawDoku
This fun Sudoku variation uses the same rules as traditional Sudoku, but it uses movable tiles more like a jigsaw puzzle. This is really great for those of us that tend to do better with visual puzzles. Use the options button to set the size of the grid, the difficulty, and whether to use numbers, letters or symbols.Samurai Sudoku
When regular 9x9 Sudoku games have become too easy for you it is time to move on to this challenging variation. Samurai Sudoku uses five overlapping 9x9 grids. Each puzzle is created by hand and there is one unique solution that requires no guessing. There is a new puzzle every day and you can also access the archive of past puzzles.Traditional Sudoku
For those looking to play a standard 9x9 Sudoku game this version by Thomas Weibel is a great choice. The game is coded in dynamic HTML and will work in almost any browser and any operating system. Each puzzle is generated on demand by a mouse click.There are four difficulty levels and you can change between three number colors as you play to better track what you have entered. You can also turn automatic verification on or off as you like. The puzzles are easy to print. You could create an entire book for offline use if you wanted.