Diwali

Diwali (also spelled Devali in certain regions) or Deepavali, popularly known as the "festival of lights", is celebrated between mid-October and mid-November for different reasons. For Hindus, Diwali is one of the most important festivals of the year and is celebrated in families by performing traditional activities together in their homes. For Jains, Diwali marks the attainment of moksha or nirvana by Mahavira in 527 BC.
Deepavali is an official holiday in India, Nepal, Sri Lanka, Myanmar, Mauritius, Guyana, Trinidad & Tobago, Suriname, Malaysia, Singapore, and Fiji.
The name "Diwali" is a contraction of "Deepavali" (Sanskrit: दीपावली Dīpāvalī), which translates into "row of lamps". Diwali involves the lighting of small clay lamps (diyas or dīpas) in Sanskrit: दीप) filled with oil to signify the triumph of good over evil. During Diwali, all the celebrants wear new clothes and share sweets and snacks with family members and friends.
The festival starts with Dhanteras on which most Indian business communities begin their financial year. The second day of the festival, Naraka Chaturdasi, marks the vanquishing of the demon Naraka by Lord Krishna and his wife Satyabhama. Amavasya, the third day of Deepawali, marks the worship of Lakshmi, the goddess of wealth in her most benevolent mood, fulfilling the wishes of her devotees. Amavasya also tells the story of Lord Vishnu, who in his dwarf incarnation vanquished the Bali, and banished him to Patala. It is on the fourth day of Deepawali, Kartika Shudda Padyami, that Bali went to patala and took the reins of his new kingdom in there. The fifth day is referred to as Yama Dvitiya (also called Bhai Dooj), and on this day sisters invite their brothers to their homes.
While the story behind Deepavali and the manner of celebration varies from region to region (festive fireworks, worship, lights, sharing of sweets), the essence is the same – to rejoice in the Inner Light (Atman) or the underlying Reality of all things (Brahman).