Sudoku Assistenten is a free program that can teach both beginners and advanced sudokusolvers more about sudoku through its advanced hint and analytical features. It will let you both type in or copy/paste any sudoku into the program and then go on to solve it or accurately estimate its difficulty. It is also the only program that will let you create your own sudoku from scratch and then go on to share them on the programs online forum.

Exciting, challenging puzzle game where you fill energy tubes of varying colors.