People of Orissa, West Bengal and Assam worship Goddess Lakshmi on the full moon day of lunar month Ashwin, which is known as Kojagara Puja. It is also more popular by the name Bengal Lakshmi Puja. Kojagara Puja Purnima is popularly known as Sharad Purnima in many parts of India.
However, in most parts of India people worship Goddess Lakshmi on Amavasya Tithi during Diwali.
At night, the goddess Lakshmi is worshiped and the night watch is observed. According to a legend, once a king fell in bad days, and was in great financial difficulties, but his queen observed this eve and that evening, and worshiped the goddess of wealth, Laxmi. Therefore, they were blessed by the goddess and regained their prosperity. In the cult of the night he offered the goddess lakshmi as well as Lord Indra.
It is also believed that on that day, as the moon and the earth are very close to each other, the lunar rays have certain healing properties to nourish the body and the soul.
Celebration:
Some people believe that tonight, Laxmi will visit people and show her pleasure among those she finds awake. Therefore, the night is devoted to the festival and several fun games, in honor of the goddess. So people are sit in the moonlight by singing songs, or remain amused in another way. They rapidly pull solid food and consume only liquids such as coconut water or milk. The milk is boiled until thickened, and the milk masala (called kheer, a combination of ready-to-use dry fruits) is added and drunk. There is also a tradition of having fresh milk and rice flakes tonight.