Nāg Panchamī (Devanagari: नाग पंचमी) is a festival during which religious Hindus in some parts of India worship either images of or live Nāgas (cobras) on the fifth day after Amavasya of the month of Shraavana. Traditionally, married young women visit their premarital households to celebrate the festival. Especially in villages in India, a traditional aspect of the celebration involves joyous swinging by young women on swings temporarily hung on tree branches.
According to Puranic scriptures, Brahma’s son Kashyapa had four wives. The “first” wife gave birth to Devas; the second, to Garudas; the third --named Kadroo--, to Nāgas; and the fourth, to Daityas. Nāgas were the rulers of Pātāl-Loka.
(... from Wikipedia on 2012-04-18 00:07:30)