Sharad Poornima observed today means a night of celebrating the full moon. It is also called the Kaumudi (moon light) celebration. After the heavy rains, the clear sky and full moon is a beautiful sight. This is also the day when Sri Lakshmi Devi is worshipped and devotees stay awake the whole night singing and worshipping Mother Lakshmi so that on her night rounds She finds them awake and showers them with wealth.
This is the night when kheer is prepared and kept in the moonlight, which the devotees love to partake of. According to the Ayurveda, the moon is believed to be close to earth on this day and the moon’s rays contain healing properties that fall on the rice flakes.
On this full moon night of Ashwin month, Sri Krishna is supposed to have danced with the Gopis and performed Raasleela. That is why it is also called raas leela divas and people fast on this night. In Gujarat, devotees perform garba and raas.
Krishna was of 10 years or less at that time. The Gopis wanted Krishna as their husband and to fulfill this wish fasted for one whole month--- Katyayani vrata. At the end of this month, Krishna robbed them of their ego (clothes) and promised that He will perform raas with them.
On that moonlit night, Krishna’s melodious note on His flute, played in the woods adjoining the Yamuna, went all the way to the ears of the gopis. They were all captivated by the bliss. They came running to where He was playing the flute.
Heaven and Nature watched a magnificent divine romantic dance of several Krishnas with several Gopis. Everyone linked their arms together to encircle Him. Between each pair of Gopis, there was a Krishna. Every Gopi had one Krishna on her left and another Krishna on her right, thereby symbolising that He had robbed them of their minds and thought power.