Mahashivratri is very significant for people who are on the spiritual path. It is also very significant for people who are in family situations, and also for the ambitious in the world. People who live in family situations observe Mahashivratri as Shivas wedding anniversary. Those with worldly ambitions see that day as the day Shiva conquered all his enemies.
Legends apart, why this day and night are held in such importance in the yogic traditions is because of the possibilities it presents to a spiritual seeker. Modern science has gone through many phases and arrived at a point today where they are out to prove to you that everything that you know as life, everything that you know as matter and existence, everything that you know as the cosmos and galaxies, is just one energy which manifests itself in millions of ways.
This scientific fact is an experiential reality in every yogi. The word yogi means one who has realized the oneness of the Existence. When I say yoga, I am not referring to any one particular practice or system. All longing to know the unbounded, all longing to know the oneness in the Existence is yoga. The night of Mahashivratri offers a person an opportunity to experience this.