According to one of the most popular legends, Shivaratri is the wedding day of Lord Shiva and Parvati. It is also believed that Lord Shiva performed 'Tandava', the dance of the primal creation, preservation and destruction on this auspicious night of Shivaratri. According to another popular legend, described in Linga Purana, it was on Shivaratri that Lord Shiva manifested himself in the form of a Linga for the first time. Since then, the day is considered to be extremely auspicious by the devotees of Shiva and they celebrate it as Maha Shivaratri - the grand night of Shiva.
Shiva devotees observe strict fast on Maha Shivaratri, with many people having only fruits and milk and some not even consuming a drop of water. Worshippers dutifully follow all the traditions and customs related to Shivaratri festival, as they strongly believe that sincere worship of Lord Shiva, on the auspicious day, releases a person of his sins and also liberates him from the cycle of birth and death. As Shiva is regarded as the ideal husband, unmarried women pray for a husband like Him, on Shivaratri. On the other hand, married women pray for the well being of their husbands, on this auspicious day.
On Maha Shivratri, devotees wake up early in the morning and take a bath, if possible in river Ganga. After wearing fresh clothes, they visit the nearest Shiva temple, to give ritual bath to the Shiva Lingum (with milk, honey, water etc). The worship continues the whole day and whole night. Jaagran (nightlong vigil) might also be observed in Lord Shiva temples, where a large number of devotees sing hymns and devotional songs, in praise of Lord Shiva. In the morning,g devotees break their fast by partaking the prasad offered to Lord Shiva, after the aarti, the night before.
Maha Shivaratri Date 2010 - 12th February.

Maha Shivratri Festival Celebrations
In the Morning
The devotees of Lord Shiva wake up early in the morning to take a ceremonious bath, after which, they would wear new clothes, smear bhasm (holy ashes) on their forehead and head towards the nearest Lord Shiva temple to take part in the celebrations. On the other hand, if they are at home, they would conduct a puja in the morning, by offering Bilwa leaves, flowers and garlands to the deity and thereafter, observe a fast for the entire day. A certain diet is formulated especially for the day, which consists of fruits and beverages (including tea, milk and coffee) as the food for the day.
Celebrations At Temple
Lord Shiva temples are decorated beautifully with festoons, on the wonderful occasion of Mahashivaratri. Apart from the usual pujas of the temple, special pujas are conducted to make the day different from the ordinary. On the festival, as many as six types of Abhisheks can be witnessed, each using milk, ghee, sugar, honey, water and sandalwood paste. The priest would chant mantras and conduct the pooja, while the devotees would queue up to have a glimpse of the rituals performed at the altar and offer prayers to the deity. The devotees would often offer incense sticks, dhoop, Bilwa leaves and garlands to the temple, which are offered to the Shiva Linga.
Celebrations In the Night
The merrymaking reaches its peak in the night of Mahashivratri, when devotees of Lord Shiva would sing songs, bhajans, chant mantras and offer prayers to the Almighty. The devotees would continue to observe their fast. In fact, they would remain at the temple premises all through the night, to take part in the keertans or jaagrans that are arranged by the temple authorities, for the festival. The devotees are served tea occasionally, to keep them awake during the night. Either the devotees themselves would sing the bhajans or professional singers are called upon on the festival, to serve the purpose. The celebrations of Maha Shivaratri would culminate only in the dawn of the next day, when the devotees would break their fast by eating the prasad that was offered to the deity in the previous night.
Importance In Hinduism
According to the Hindu mythology, Lord Shiva declared that the rituals performed by his devotees on the 14th day of the dark fortnight in the month of Phalgun please him the most. Therefore, year by year, the day is observed as Mahashivratri, wherein devotees observe fast, sing songs and bhajans and offer prayers to the Almighty to seek his blessings. Pujas conducted in Lord Shiva temples during the day have significance too. This is because the rituals are conducted strictly in accordance with the method that is prescribed in Shiva Purana, a Hindu epic. According to the Purana, poojas are conducted once in every three hours, on Maha Shivaratri.
Importance In Human Lives
It is believed that the devotion of Lord Shiva on Mahashivaratri would freed the devotee from the past sins. Moreover, the devotee would reach the adobe of Lord Shiva and live there happily, because he/she is liberated from the cycle of birth and death, once he/she attains moksha or salvation. Therefore, all the devotees of Lord Shiva would flock the temples to offer their prayers. To serve the purpose, jujube fruits, stalks of Bilwa leaves, flowers and garlands are offered to the Shiva Linga by the devotees. If the devotee celebrates the festival at home, he/she would perform the Mahashivratri Puja by taking a holy bath (in warm water) early in the morning, wearing new clothes and then smearing bhasm (holy ash) on their forehead.
Importance For Women
Maha Shivaratri is especially important for women. Ladies, both married and unmarried, would perform Shiva Puja and observe fast with great devotion and sincerity. This is predominantly done to appease Lord Shiva along with his consort Goddess Parvati, who is often called Ma Gauri. It is believed that Ma Gauri bestows marital bliss on unmarried women and blesses the married women with healthy and blissful married life. Since Lord Shiva is regarded as the ideal husband by the Hindu women, the unmarried women would not miss to observe the fast on Shivaratri.

Significance
Hindu mythology suggests that the observance of vrat on Mahashivratri helps one to attain control over the two great forces that afflict man - rajas guna (the quality of passionate activity) and tamas guna (the quality of ignorance). When the devotee observes a fast with discipline and spends the entire day at the feet of Lord Shiva, his/her mind is controlled. Moreover, evils like lust, anger and greed are subdued, thereby acquiring control over rajas guna. When he/she wakes vigil throughout the night of Maha Shivaratri, he/she develops the ability to conquer the evils of tamas guna too. Therefore, Mahashivratri vrat is significant.
Fasting Rules
Traditionally, people who observe fast on Mahashivaratri would take bath early in the morning, with warm water and black sesame seeds. However, nowadays, people prefer to take a hot water shower, in the morning. By bathing, it is believed that the bodily impurities are washed away. After wearing new laundered clothes, the devotees would visit the nearest Lord Shiva temple to worship the deity. The ritual of bathing Shiva Linga with milk and honey takes place in temples of the diety, on the festival. While in the temple, the devotees would sing devotional songs and bhajans, to invoke Lord Shiva. All through the day and night during the festival, they would indulge in chanting of three words 'Om Namah Shivaya'.
Food For Mahashivratri Vrat
A diet is followed by the devotees of Lord Shiva, on Maha Shivaratri. On the day, they would abstain from food made with rice, pulses or wheat. However, the devotees may eat fruits and drink tea, milk or coffee during the fast, if they have not observed nirahar vrat (fast without the consumption of any form of foodstuff). In the evening, after performing puja, they would break the fast by eating rotis made of singhare ka atta (kuttu ka atta) and sabut dana kheer (dessert made of sago). Sendha namak (rock salt) is used to cook food for the fast. To offer the deity, people would prepare dishes such as potato pumpkin pancakes, lauki ka halwa (sweet dish made of bottle guard), thandai etc.