I wrote a small command-line program this morning called callistevents (from Calendar List Events). It is a Mac OS/X program that lists all the events in a specific calendar between 2 dates.
I wrote this program because I have been using Pomodoros to time-box my tasks each day. My Pomodoro software logs all the time-boxes I do to a calendar called “Pomodoros”. I wanted to sum up all the time-boxes so I could keep track of my productivity each day.
I hope this is useful to other people. If so, you can find it on GitHub.