A Streak Sheet with Timers
Last year, several timers appeared at the bottom of the intro text on the home page of my site. I called them streaks. One is about alcohol, another is about language learning.
I realized the importance of consistency a long time ago when I was doing sports. Once you break a streak, there is an immediate risk of giving up the activity entirely. So the idea is this: in a task-tracking system—or any other system where recurring information is entered—you add a recurrence marker so you can track continuity of the process. Examples include taking medication, sports/sex/morning exercise, language learning, drinking or not drinking alcohol, and so on.
A good feature would be not only starting a timer that motivates and provides a measurable signal, but also setting reminders that motivate you either to do something or, on the contrary, not to do something. In the end, the application would allow you to collect data, compare it, look for patterns in time series, and draw conclusions—the usual story.