1-Lent is a preparation for the celebration of Easter.
2-Lent is the Old English word for spring.
3-There is actually more than 40 days of Lent. Lent runs from Ash Wednesday until the Mass of the Lord's Supper on Holy Thursday.
4-Sundays are part of Lent. Some will say that they are not part of Lent because we celebrate the Mass, therefore Sundays are exempt. It would then follow that we would be allowed to have those things that we give up for Lent on Sundays. In fact, the Sundays of the Lenten Season are called “First Sunday of Lent”, “Second Sunday of Lent”, “Third Sunday of Lent”, and so on. It is clear by these titles that Sundays are part of Lent. But we can still indulge on Sundays, if we want to, because what we give up for Lent is voluntary.
5-Lent is 40 days long because of tradition. Moses stayed on the mountain for 40 days. Nineveh was given 40 days to repent, and most of all Jesus fasted and prayed in the wilderness for 40 days before starting his ministry.
6-During Lent it is customary to give up something that we enjoy or rely upon to help us discipline our will so that we are not slaves to pleasure. In this way, we can better train to detach ourselves from the wants of this world and allow ourselves to become more perfectly in-line with the will of God.