Though feared and reviled by crossword purists, Sudoku has become one of the most popular puzzles in recent memory, appearing in countless newspapers, computer games, and even Nintendo's Brain Age. The rules are simple: 3 regions of 3 squares each form a 9x9 grid, every cell of which must be filled with a number between 1 and 9. Every row and every column can only have one instance of each number, and every 3x3 region must contain all 9 numbers.

Adam Lyttle's implementation, Sudoku Craving, is just as professional as his previously reviewed Solitaire Craving. The interface is clean and precise and, in addition to keeping track of your personal performance on each puzzle, comment boards and high score charts encourage community participation and competition. Sudoku Craving is a great resource for sudoku addicts looking for their daily logic fix.