About.com's 20th Century History site explores the fascinating history of the calendar in the former Soviet Union. Learn about their 5-day week calendar which didn't work out so well. I have more on the Soviet Union and on the Gregorian calendar, which we use today.

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It is very interesting article, however small note the Eternal Soviet calendar, also known as Soviet Revolutionary Calendar, in a end of 20’s and 30’s was used parallel to Gregorian calendar, than you look into the Soviet newspapers of that time you will see the parallel between to calendars . They would say for example October 22 of 1935 is a Tuesday and fourth day of fourth six day week in October. It will also say the year counting from October revolution. In October 22 of 1935 it would be the end of 17 year. All the month in a year became 30 days long, and February 30 became a valid date. The rest of 5 days became a holidays which did not belong to any days of the month or week. They were Lenin day after January 30th , Labor days – two days after April 30th, Industry Days – two days after November 7th and in leap years a leap day after February 30th. Eternal soviet calendar considered to be a mistake by Soviets and rarely mentioned by Soviet officials later on not even in a history books. The whole generations of Soviets and former Soviet people grove up not knowing existence of this calendar.