In case some people do not know what mole is, it is a unit of measurement used in science/chemistry.
Definition: A mole is the quantity of anything that has the same number of particles found in 12.000 grams of carbon-12. That number of particles is Avogadro's Number, which is roughly 6.02x1023.
Mole Day is on Oct. 23, since 1023 is in mole. 1023 can be made into 10/23, which is October 23rd.
Some puns are:
Mole, the Mexican sauce
and some others
If you have any other good puns post them in the comments!!