SudoCue
SudoCue is one of the many Sudoku-based games available for free download online. There's no doubt that Sudoku has become quite a staple for brain puzzler enthusiasts. It's easy to play, it's challenging and some even claim that it helps to improve your mathematical skills.
I'm not too sure whether it does or it doesn't but you can definitely have some fun solving those Sudoku puzzles with SudoCue.