Chol Hamo'ed - The Mundane Festival

The final 5 days of Sukkot and the middle 4 days of Passover are called Chol Hamo'ed - "Mundane Festival". They are part of the holiday but not holidays. They are regular days and holy days. We are allowed to work but not supposed to work if possible. What are these paradoxical days about? A fascinating discussion about Chol Hamo'ed, the middle days of the festivals.