Over the years, many Sudoku variants have popped up. Some of them quite interesting indeed!
One of my favorite variations is Sudoku for kids, which is just a simpler version that is a 6x6 grid instead of 9x9. The inner blocks are 3x2. My own kids enjoy playing this game very much.
Other variants include:
Super Sudoku / Sudoku 16x16 / Monster Sudoku
Same game with a larger grid
Five overlapping Sudoku puzzles
Has additional regions
More closely related to crossword puzzles
A cross between Sudoku and Kakuro
Inner blocks are random jigsaw shapes instead of squares
Initial puzzle must be filled in with clues like a crossword puzzle
Place words into a Sudoku grid and avoid duplicate letters
Another name for "Sudoku for Kids"
This site will focus on the original, 9x9 version of Sudoku. At least for now…