The image below is circulating on some social media sites – claiming it happens once every 823 years.
It is true that in 2013, March has 5 Fridays, 5 Saturdays and 5 Sundays, but it does not take 823 years to repeat this as some sites claim–more like 5, 6, or 11 years (depending on leap year). It would be nice to have a once in a lifetime experience – but this isn’t it.
However – each year (until this year) since 2001 there has been a unique event each year which will not happen again in most of our life-times. The dates: 01/01/01, 02/02/02 etc. It will indeed take 100 years before the next 01/01/01 (January 01, 2101).