The Great night of lord Shiva is called as Maha Shiv Ratri. It occurs in the luni-solar month of the Hindu calendar, on the month's 13th night/14th day prior to spring.
Importance of Maha Shiv Ratri:
On Maha Shiva Ratri there is rise in natural energy within human body allowing to do certain type of Sadhana. This Sadhana may not be suitable for everyone. Some sort of necessary preparation are required.
On Such Powerful night of energy and possibilities one should dedicate himself to lord Shiva. Many devottees stay awake whole night observe fast, meditate and perform pooja.
This is extremely auspicious occasion to perform Kalsarpa Shanti and Mrutunjaya Jaap. Performing KarlSarpa Shanti pooja on this day will be extremely fruitful and it will remove all hurdles in life. Maha Shivratri is considered as The Great Night of Shiva who is the Source of Energy to this World and also is the Saviour of this World.
It is advised in the ancient text to perform Kalsarpa Shanti at Trimbakeshwar which is considered to be the most holy Jyotirlinga among all the Jyotirlinga because of presence of Lord Bramha, Lord Vishnu along with Lord Shiva.