Well, today (for me) is October 23, a date celebrated in many high schools as Mole Day. Why you ask? Good question.
In chemistry, a mole is, as my understanding goes, just a number that represents the amount of a substance that contains as many atoms, molecules, ions, or other elementary units as the number of atoms in 0.012 kilogram of carbon 12. The number is about 6.022 × 10^23. I’m sure Sin will come in with some fancy schmancy big ol’ “I’s Gots Mes Ans Sciences Majors” and explain it more in depth.
Anyway, why October 23? Well, it could be June 2, but that wouldn’t work since most students aren’t in school then. It was decided that October 23 would be a better date due to the 10 ^ 23 part and that more students would be in school. It’s just Chemistry’s ripoff of Pi Day. It’s generally presented with fancy “A mole of so and so stuff would cover some such distance” lists. I’ve never found one about a mole of moles, so I’m mad.
The people taking the Natural Science Programme in Sweden are known for their terrible humour. I was talking to one of them and got confirmation that this is not only a rumour. One of their favourite jokes was to point at a bread crumb and say “I wonder how many mole that is!”