We can develop a set of beliefs by reading something, listening to someone or by watching something. However there is no benefit in having a belief (For centuries together the western countries believed that earth was flat and that what the kids were taught in their schools). Our culture is against belief; instead it gives a lot of importance for knowing and realization. I can tell you a very convincing story about how the universe was created, you can believe me or you may reject my theory. However none of your action is going to aid your growth. That is why seeking is important; one should know everything within.
There are only two ways of knowing things, one to explore the external and the other is to seek the internal. Anything that is not you is external so if we need to explore outside, then the whole universe is there to explore and it will take you a billion lives to have even a glimpse of a portion of the universe. That is why our spiritual process is designed to seek the internal. The force that created the universe is the same force that created us, so we can seek that force within, yoga and our way of life was designed to seek the divinity within. We used all form of aids to seek the divine within. We had special days, we have special kriyas, we have special mantras, we have yogasanas, we have certain foods and we have certain methods to speed up the process of this realization.
One such tool is Mahasivaratri. The day before the Amavasya (new moon day) of each month is called shivarathri. The shivarathri that falls in the month of Maasi (that comes in February-March) each year is considered to be the most auspicious and is celebrated as Mahashivarathri. Traditionally, one is advised to stay awake throughout the night of Mahashivarathri with an erect spine preferably.
It is a well-known fact that the gravitational pull of moon over earth is at the highest during the new moon day. One can notice the high tides on new moon and full moon days. In a subtler way they affect energies of the body and by kindling the kundalini energy and to raise it from mooladhara to higher chakras. The raising of the energies starts from shivaratri and reaches its peak on the new moon day.
Spiritual seekers and Brahmacharis shave their head on this day every month as it aids in raising the energies to the sahasra chakra. Once they attain full control of their chakras then they stop shaving.
Every shivaratri is special however the planetary positions are such on the night of Mahashivarathri, that anyone sitting the whole night with his spine erect will experience new surge in their energy. But over a period of time Bhakthi took over and people lost the procedures to be followed during the night of shivaratri and some people even watch movies all night lying in their beds.
If you are a spiritual seeker then just sit in a comfortable position with you spine erect for as long as possible during the night. If you are practicing any sadhana, then you can do it, else just sitting erect will greatly help you. If you have a good sanskrit pronunciation then you can chant Maha Mrityunjay Mantra. If you are a devotee and a worshiper of a Shiva, then you can chant any songs in your language.