There are several stories associated with Mahashivaratri. Few of them are briefly discussed here.
SAMUDRA MANTHAN STORY
During Samudra Manthan by the Gods and demons, venom emerged out of the ocean. As per the advice of Lord Vishnu, Gods approached Lord Shiva and prayed him to protect life. Pleased with their prayers, Lord Shiva drank this poison and held it in his throat. The throat became blue due to the poison (Thus Lord Shiva is also known as Neelakantha) .The prudent men advised Gods to keep Lord Shiva awake during the night. To keep him awake, the Gods took turns performing various dances and playing music. As the day broke out, Shiva, pleased with their devotion, blessed them all, and also said that whosoever worshipped him, on this day, shall be blessed with the fulfillment of his or her wishes. Since then, on this day devotees fast, keep vigil, sing glories of Lord, and meditate.
STORY OF LUBDHAK
It was the night before the no moon night, Lubdhak, who was a great devotee of Shiva, was wandering deep in the forest to collect firewood. Soon he got lost and was unable to find his way back. There he could hear the hungry tiger roaring. Lubdhak knew he could not outrun the tiger. Therefore, he climbed up a ‘bael’ tree. In order to keep himself from sleeping , he began to pull the leaves from the bael tree and dropped them one by one, each time chanting “Om Namah Shivaya”. In the morning when he descended the tree, he saw a lingan which he had missed at night. Accidentally, he had been dropping leaves on the lingam. This was the 13th night of the waxing moon of the month of Phalgun and came to be celebrated as Mahashivratri.
REUNION OF SHIV AND PARVATI
Sati’s marriage with Shiva was opposed by her father, king Daksha. At a Yagna, the king insulted Shiva by ignoring his presence which made Sati so furious that she ended her life by jumping into the sacrificial fire. Lord Shiva unleashed his rage by performing the ‘Tandav Nritya’. He then destroyed Daksha’s kingdom and marched back to the Himalyas. The Gods, then feared that the cruelty of Shiva’s penance might bring an end to the world, revived Sati in the new avatar of Parvati. Shiva-Parvati then re-married. Thus,this divine reunion is celebrated on Maha Shivaratri.