Celebrations take place throughout the night of Shivaratri. The planetary positions on this night are unique and, thus, there is an increase in energy levels. It is believed that on this day, Lord Shiva married the goddess, Parvati.
On Shivaratri, devotees visit temples to offer prayers, chant mantras and take part in the pujas performed throughout the night. Bel leaves are offered to the god as it is believed that such offerings will absolve people of all sins and lead to liberation. According to yoga philosophy, Shiva is the Adi Yogi, or the first yogi.
Shiva is considered to be the spine that was the source for all spiritual knowledge. Staying awake throughout the night of Shivaratri with the spine erect helps the devotee to experience a powerful upsurge of energy. Yoga can be used to further one's receptivity to this energy. It is best to assume a yogic pose that keeps the spine erect, but one that's simple enough to remain comfortably in the pose for a longer time.
It is also believed that it was on Maha Shivaratri that Lord Shiva performed Tandava, a dance that signifies creation, destruction, support, illusion and grace.