"Nava-ratri" literally means "nine nights." The 9 Divine Nights.
Nava – that means 'new' – denotes 'nine' the number to which sages attach special significance. Hence we have Nava-ratri (9 nights), Nava-patrika (9 leaves / herbs / plants), Nava-graha (9 planets), and Nava-Durga (9 appellations).
During Navaratri, we invoke the energy aspect of God in the form of the universal mother, commonly referred to as "Durga," which literally means the remover of miseries of life. She is also referred to as "Devi" (goddess) or "Shakti" (energy or power). It is this energy, which helps God to proceed with the work of creation, preservation and destruction. God is motionless, absolutely changeless, and the Divine Mother Durga, does everything. Her energy is imperishable. It cannot be created or destroyed. It is always there.
Navaratri is divided into sets of three days to adore different aspects of the supreme goddess. On the first three days, the Mother is invoked as powerful force called Durga in order to destroy all our impurities, vices and defects. The next three days, the Mother is adored as a giver of spiritual wealth, Lakshmi, who is considered to have the power of bestowing on her devotees the inexhaustible wealth. The final set of three days is spent in worshipping the mother as the goddess of wisdom, Saraswati. In order have all-round success in life, the blessings of all three aspects of the divine mother; worship for nine nights.
In 2012, Navaratri starts on October 16 and ends on October 23.
Navaratri is celebrated with nine nights of dancing. The traditional dances of Gujurat, known as garba and dandiya raas, are performed in circles with dancers dressed up in colorful clothes. Small, decorated sticks called dandiyas are used in the dandiya raas.
The worship, accompanied by fasting, takes place in the mornings. Evenings are for feasting and dancing.