Special events and other funny days

The holiday is usually celebrated on June 9th, which is depicted numerically as 6/9.

National 69 Day is one of a number of unofficial holidays of unknown origin, but that doesn’t make it any less real or any less … enjoyable … to celebrate. As its name implies, National 69 Day is dedicated to having oral sex.

Pentecost (Holiday and sunday)

Pentecost is a Christian holiday celebrated 49 days after Jesus Christ rose from the dead on Easter Sunday. On this day, the Holy Ghost appeared to the apostles in the form of tongues of fire from heaven. The day commemorates the coming of the Holy Ghost to the apostles.

It can be discussed how comfortable, delicious and hygienic it is to ride naked, but it must be good for the environment.
And that's why there are thousands of people in large parts of the western world stepping forward and throwing away their clothes on June 9th.