Shamlessly Stolen from: https://en.wikipedia.org/wiki/Pomodoro_Technique
The Pomodoro Technique is a time management method developed by Francesco Cirillo in the late 1980s. The technique uses a timer to break down work into intervals, traditionally 25 minutes in length, separated by short breaks. Each interval is known as a pomodoro, from the Italian word for 'tomato', after the tomato-shaped kitchen timer that Cirillo used as a university student.
This app uses Google apis, as they are so user-friendly and easy to set up. Pomodoro Productivity is strongly based around google functionality, and should seemlessly interface with Google Calendar. Note that if you don't live in the America/Los Angeles, the app won't work, and also it probably won't work if you aren't using an up-to-date version of Google Chrome.