Okay, not every geek is a Sudoku fan, but perhaps they just haven't been converted yet. In case you don't know, Sudoku is an addictive reasoning game that's suddenly gotten incredibly trendy. If you want to play, but don't want to buy the books, the free Sudoku Widget generates random puzzles on your desktop - all day.
It features four different levels of difficulty and will show you the correct answer when you guess incorrectly. It also allows for “pencil” marks for temporary numbers, has high scores and allows for blank puzzles. Mac users can download it from Apple.
If you're a PC user, or just want additional playing tips, visit Sudoku.com.