iOS: Tinker is a minimalistic iPhone app that makes you schedule tasks and set a specific duration for them. It will alert you when it's time to start, show you progress during the task's set period, and notify you when you're supposed to be done.
Each task is in the form of a circle with a coloured outline, which gradually reduces clockwise as time passes. You can tap the circle at any time to pause it, or swipe it out of the screen to mark it as completed. To create a new task, pinch out with two fingers.
There's no dearth of to-do apps on the App Store, but Tinker's simple and good-looking approach makes you want to use it more than others. The design is focussd on the task and the time, and there's something about the ticking progress bar that reminds you of a traditional clock; somehow, it puts the time into better perspective.
I've been using Tinker for a few days now and there's a productivity niche it has found in my routine. While you can schedule tasks for days into the future, that's not the ideal use of this app. Tinker is best for setting a time and schedule for tasks that come up inescapably in the course of the day, like an odd chore or a personal deadline for finishing an article.
Don't think of it as a replacement for your favourite to-do app for the iPhone. Instead, use Tinker to complement that app and set short-term goals or add small chores.