The one I go back to over and over is Cookie Clicker (orteil.dashnet.org/cookieclicker/) any time I feel like getting a watch that counts my steps or a Tesco Club Card or any other gamification device -- I play the master of gamification. Or I watch the button, 13 days in and 55, 54, 53, click! Idiot, 59, 58, 57, 56, 55, click! Idiot, 59, 58, 57....