Lord Krishna is a major deity in Hinduism. He is worshipped as the eighth avatar of the god Vishnu and also as the supreme God in his own right. He is the god of compassion, tenderness and love in Hinduism, and is one of the most popular and widely revered among Indian divinities. Lord Krishna's birthday is celebrated every year by Hindus on Krishna Janmashtami according to the lunisolar Hindu calendar, which falls in late August or early September of the Gregorian calendar.
Lord Krishna is usually depicted with a flute in his hand. He is traditionally considered a master of the bamboo flute. This is revered as Lord Krishna's divine instrument and is often associated with Lord Krishna's Rasa lila dance. The Rass lila or Rass dance is part of the traditional story of Lord Krishna as described in Hindu scriptures where he dances with Lordess Radha and her sakhis. It takes place one night when the Gopis of Vrindavana, upon hearing the sound of Krishna's flute, sneak away from their households and families to the forest to dance with Krishna throughout the night, which Krishna supernaturally stretches to the length of one Night of Brahma, a Hindu unit of time lasting approximately 4.32 billion years.
Some of the best Lord Krishna's flute music on youtube are below:
Information source from youtube and Link.