Wordoku is a free online puzzle game that combines the elements of Sudoku and crossword puzzles. Players are challenged to fill a 9x9 grid with letters, forming words both horizontally and vertically, while ensuring that each row, column, and 3x3 box contains different letters. With its 150 pre-made levels, Wordoku offers hours of entertainment and brain-teasing fun, making it an excellent choice for passing the time when bored. This game is a great way to improve vocabulary and logical thinking skills.