Each month there is day known as Sivaratri and once a year there is Mahasivaratri (maha=great); The Great Festival of Shiva. The dates of these occasions correspond to the phases of the moon and it is believed that the mind (which is adversely affected by the power of the moon) is less susceptible to low, animalistic forces and thus more tractable to the power of meditation and prayer.
It is for this reason that Mahasivaratri is believed to be the one 24-hour period in the year which is of the greatest benefit. It has been stated in the scriptures that if a man fasts, stays awake and meditates for the whole of Mahasivaratri, it will give him his best chance to achieve mastery of the mind and attain liberation.
Mahashivaratri always falls on the fourteenth day of the dark fortnight of Phalguna (February-March), and is dedicated to the worship of Lord Shiva. (Mahashivaratri this year, 2007 falls on Friday, February 16th). On this day devotees sing Shiva bhajans, recite verses from scriptures, offer prayers in the morning and evening, and some observe fasting throughout the day. People visit Shiva Temples and in the case of Arunachala, premier Shiva site of South India, circumbulation of Arunachala Hill is observed by many.
The name Shiva signifies a quality that means 'Auspicious' or 'The Auspicious One'. To a few, Shiva is Paramatman, Brahman, the Absolute, but many more prefer to see Shiva as a personal God given to compassion for his worshippers, and the dispenser of both spiritual and material blessings. Related to the Absolute concept is Shiva as Yoganath, the Lord of Yoga, wherein he becomes teacher, path and goal. As such he is the Adi Guru or Highest Guru of sannyasins who have renounced the world to attain the Absolute.
One of the early traditions, is Shiva in the form of Dakshinamurti; the South-Facing Guru. In this form, seated on a low platform, with one leg hanging down in front, he communicated the Sanatana Dharma or Eternal Wisdom to the four Kumaras who appeared early in creation. The Guru spoke no words but taught them by the transmission of mind-to-mind, and its purpose was to show that man can realise the Absolute when the human mind is in complete equipoise with the Cosmic Mind.
While almost all other festivals are celebrated during the day, Mahashivaratri is celebrated at night, which stands for all that is evil: injustice, ignorance, darkness, sin, violence, treachery, falsehood, and misfortune. Mythology says that Shiva appeared to save the world from Tamoguna (darkness and ignorance).
One legend concerning Shivaratri, is of a hunter named Lubdhaka, who after killing birds in a forest, was chased by a hungry lion. The hunter climbed a Bilva tree to save himself from the lion's attack. The lion waited throughout the entire night at the bottom of the tree for its prey. In order to stay awake to avoid falling from the tree, the hunter kept plucking the leaves of the Bilva tree and dropped them below. The leaves fell on a Shiva Lingam that happened to be located at the bottom of the tree. Shiva was pleased by the inadvertent offering of Bilva leaves by the hunter, and saved him in spite of his sin in killing the birds.
On Maha Shivaratri, Lord Shiva is Lingodbhavamurti, the pillar of fire that spans all, with no beginning and no end. The devout believe that they are on their way to oneness with Shiva, that they will join with the Supreme after hours of darkness spent in fasting and prayer. The worship of Lingodbhavamurti is with the leaves of the bilva, gathered from quince trees. The lingam is showered, unceasingly, with basketfuls of these, and other flowers, just as Lubdhaka, the hunter in the above story once did.
Another legend traces the origin of this festival to the churning of the Ocean of Milk by devas (gods) and asuras (demons). It is said that when both gods and demons were churning the Ocean of Milk to obtain amrita (water of immortal life), they came across many unusual substances, including the deadly poison Kalakuta. As soon as they touched the poison, it exploded into poisonous fumes that threatened to envelope the entire Universe with darkness. When the destruction of the Universe seemed inevitable, the gods ran for assistance from Brahma and Vishnu, but neither was able to help. At last they ran to Lord Shiva, who raised his trident and condensed the fumes. In order to save the creation, Shiva swallowed the poison without spilling a single drop. The poison left a dark blue mark on Shiva's throat. The gods praised and worshipped Shiva for saving the universe.
The Ocean of Milk represents the ideal world that is full of peace and happiness for all human beings. Churning the Ocean of Milk signifies the human activity in the world. The amrita symbolizes happiness and the poison represents human greed and selfishness. Shiva symbolizes the atman (self), and worship of Shiva denotes meditation and contemplation by an individual on his or her own self.
Thus the only way to achieve peace and happiness is by worshipping Shiva at night, that is, by meditating on one's own self during the night when the individual is free from the distractions of the physical world. When the individual attains self-knowledge, he or she can live in the world without being affected by anger, greed, and selfishness, the three enemies of one's soul. MahaShivaratri symbolizes the worship of the atman within.