The French Revolutionary Calendar -- sometimes also called the Republican Calendar -- was introduced during the years following the French Revolution. Overthrowing the ridiculous and illogical Gregorian calendar, the revolutionaries instituted a decimal calendar, keyed to the seasons, with 10-day weeks and 10-hour days. Each day was named for a flower, herb, animal or plant, rather than the saints that the Catholic calendar has.
The calendar reportedly did poorly because people only got one day out of 10, instead of one out of 7. I think people probably just didn't want to learn a whole new calendar. Then again, they learned the metric system, so who knows?