Mahasivrathri -the deeper meaning and objective

Maha Shivratri or Maha Sivaratri or Shivaratri or Sivaratri (Night of Shiva or "Great Night of Shiva") is a Hindu festival celebrated every year on the 13th night/14th day in the Krishna Paksha (waning moon) of the month of Maagha (as per Shalivahana) or Phalguna (as per Vikrama) in the Hindu Calendar (that is, the night before and day of the new moon). The festival is principally celebrated by offerings of Bael (Bilva) leaves to the Lord Shiva, all day fasting and an all night long vigil.
The deeper yogic meaning and objective within Mahasivrathri is:Mahasivrathri is the day & night of the yogi. Mahasivrathri is a once a year celebration of Lord Siva, the awake Spirit within each of us. For several thousands of years, yogis and nearly 60% of all householders, i.e, ordinary people in India, observe this auspicious day by staying up all night chanting and singing to Lord Siva. Mahasivrathri is the gift of realized Sages to enable everyone experience turiya, the state of higher consciousness.
Observing Mahasivrathri is transforming as we awaken to whom we truly are. Lord Siva, the dissolver of ego enables clearance of past karmic negatives that have blocked us from our true potentials. Mahasivrathri is rejuvenative as we tune into the eternal yogi within ourselves as the surrender of our body consciousness to the awake soul, the eternal yogi. The objective of Mahasivrathri is to experience turiya, the realm of enlightenment. Proximity of the mind with Source does align our thoughts to be empowered as we are in touch with our inner wisdom of calm, serenity, inspiration, abundance and knowing.

Source http://en.wikipedia.org/wiki/Maha_Shivaratri