Losing Track of Time with Sudoku: A Puzzle That Sneaks into Your Life There are very few things in my life that make me forget time exists. Most activities come with a clock in my head — deadlines, notifications, reminders constantly pulling me back to reality. But every once in a while, I find myself looking up and realizing an hour has passed without me noticing. That usually happens when I’m playing Sudoku. https://sudokufree.org