Lately I've been trying out this productivity technique called The Pomodoro Technique. The basic idea is that you write down a task to work toward, work hard for 25 minutes, and then rest for 5 minutes--repeating until the task is complete.
Since most of my time is spent in front of a computer, I looked for a timer that would show me the 25-minute clock counting down. I didn't find exactly what I was looking for, so I decided to write my own as my first open source project.
The name of the program is Pomo. You can get it here. Just download and run it.