A very interesting story about Dhanteras Festival says that once the sixteen year old son of King Hima was doomed to die by a snake-bite on the fourth day of his marriage as per his horoscope. On that particular fourth day of his marriage his young wife did not allow him to sleep. She laid all the ornaments and lots of gold and silver coins in a big heap at the entrance of her husband's boudoir and lighted innumerable lamps all over the place. And she went on telling stories and singing songs.
When Yama, the god of Death arrived there in the guise of a Serpent his eyes got blinded by that dazzle of those brilliant lights and he could not enter the Prince's chamber. So he climbed on top of the heap of the ornaments and coins and sat there whole night listening to the melodious songs. In the morning he quietly went away. Thus the young wife saved her husband from the clutches of death. Since then this day of Dhanteras came to be known as the day of "Yamadeepdaan" and lamps are kept burning throughout the night in reverential adoration to Yam, the god of Death.
One famous story is about Lord Dhanvantari and his service to mankind. According to another popular legend, during the churning of ocean (Samudra Manthan / Sagar Manthan) by the Gods and the demons, Dhanvantari - the physician of the Gods and an incarnation of Vishnu came out of the ocean on the day of Dhanteras, with a pot of Ayurvedic that was meant for the welfare of the humankind. Since then the day came to be celebrated as the day of Dhanteras. This day also marks the arrival of Goddess Lakshmi, which is celebrated by drawing small footprints of the deity, with rice flour and vermilion powder.