France actually tried that right after the Revolution. They adopted the metric system, which included a revolutionary calendar with 12 months, each consisting of three 10-day weeks.
The Republican calendar year began at the autumn equinox and had twelve months of 30 days each, which were given new names based on nature:
o Vendémiaire (from Latin vindemia, "grape harvest") Starting Sept 22, 23 or 24
o Brumaire (from French brume, "fog") Starting Oct 22, 23 or 24
o Frimaire (From French frimas, "frost") Starting Nov 21, 22 or 23
o Nivôse (from Latin nivosus, "snowy") Starting Dec 21, 22 or 23
o Pluviôse (from Latin pluvius, "rainy") Starting Jan 20, 21 or 22
o Ventôse (from Latin ventosus, "windy") Starting Feb 19, 20 or 21
o Germinal (from Latin germen, "germination") Starting Mar 20 or 21
o Floréal (from Latin flos, "flower") Starting Apr 20 or 21
o Prairial (from French prairie, "pasture") Starting May 20 or 21
o Messidor (from Latin messis, "harvest") Starting Jun 19 or 20
o Thermidor (or Fervidor) (from Greek thermon, "summer heat") Starting Jul 19 or 20
o Fructidor (from Latin fructus, "fruit") Starting Aug 18 or 19
Note: Fervidor appeared on many printed calendars for Year II of the French Republic (September 22, 1793 - September 21, 1794).
The English translations stated above are approximate, as most of the month names were new words coined from French, Latin or Greek. The endings of the names are grouped by season.
In England, people mocked the Republican Calendar by calling the months: Wheezy, Sneezy and Freezy; Slippy, Drippy and Nippy; Showery, Flowery and Bowery; Wheaty, Heaty and Sweety.
Ten days of the week
The month is divided into three décades or 'weeks' of ten days each, named simply:
* primidi (first day)
* duodi (second day)
* tridi (third day)
* quartidi (fourth day)
* quintidi (fifth day)
* sextidi (sixth day)
* septidi (seventh day)
* octidi (eighth day)
* nonidi (ninth day)
* décadi (tenth day)http://windhorst.org/calendar/#Brinton