The Pomodoro Technique ® was developed by Francesco Cirillo to facilitate productive, focused work. It is deliciously simple. Set a timer for 25 minutes — a "Pomodoro" — and focus on one task until the timer is done. Then take a short break. After four Pomodoros take a longer break. Repeat.
This is my own take on a Pomodoro web app. For fun, I added animations to visualize time remaining in the current interval. The timer's background turns from red to a light coral as the red circular segment's area shrinks relative to the elapsed time (implemented via the Canvas API). The favicon is replaced once every 10% of time elapsed with a similar graphic. Future improvements being considered include a history log and integrated todos.
I must provide kudos to the TomatoTimer which I used until developing my own app.