Diwali is actually celebrated in honor of Lord Rama and his wife Sita, returning to their kingdom of Ayodhya, following Rama and monkey god Hanuman's defeat of the demon King Ravana and rescue of Sita from Ravana's evil clutches.
In 2013, Diwali starts with Dhanteras on November 1. Each day of the festival has a different meaning. The main festivities take place on the third day (November 3rd, this year), while the fourth day is celebrated as New Year's Day. Merchants open fresh accounts for the new year, and offer prayers. On the fifth and last day, brothers and sisters get together and share food, to honor the bond between them.
On the third day of Diwali, lots of small clay lamps (diyas) and candles are lit and placed in houses. Fireworks are sett off everywhere, giving Diwali its name of “Festival of Lights.” People also clean and decorate their homes with folk art (rangoli) buy new clothes, gamble, and give each other gifts and sweets.
Rangoli remind me of Amish Hex Signs, common in Lancaster, PA.