"Three times shall you celebrate for me in the year"—Exodus 23:14.
We are commanded to celebrate in the Holy Temple thrice yearly [during the festivals of Passover, Shavuot and Sukkot].
This festivity entails the offering of a Festival Offering, known as the Chagigah Offering.
Women are exempt from this mitzvah.
This is one of the three mitzvot associated with the festivals; the other two are Pilgrimage and Rejoicing.