iOS: Using a timer while you work is essential to the Pomodoro productivity technique. If you have an iPhone or iPad nearby while you work, try Minimalist Timer. It's free, it's lightweight, and you won't get stressed out looking at it as it ticks down.
Minimalist Timer, as the name implies, has a simple UI. There's a large dial in the centre of the screen, and you can tap and "turn" the dial to set the timer. One full turn is 60 minutes, and you can keep turning to set the timer for however long you need. A plus and minus on either side of the dial let you quickly add or subtract an hour, and buttons on the bottom let you add one, five or 60 minutes to the current timer setting.
The app's settings allow you to set the alarm sound, vibrate instead of (or in addition to) beeping, auto-start the timer as soon as you set it, hide the controls so you get a truly minimal view and more. It's free with ads, but you can kill them via a $0.99 in-app purchase. Give it a try and let us know what you think in the comments below.
Minimalist TImer [iTunes App Store]