Just a quick kata, converts the current date and time to date and time in the Calendrier républicain.
see: http://fr.wikipedia.org/wiki/Calendrier_r%C3%A9publicain
It has a lot of shortfalls and is by no way accurate since there are some special rules and the calendar of the revolution has been abandoned long time. Also the calculation of the year is false, since the year of the revolution starts on 22th of september.
It was fun to made, so have fun using it.