Krishna Janmashtami

Krishna Janmashtami, also known simply as Janmashtami or Gokulashtami, is an annual Hindu festival that celebrates the birth of Krishna, the eighth avatar of Vishnu. It is observed according to the Hindu calendar. It is on the eighth day of the Krishna Pakshain Shraavana or Bhadrapad (depending on whether the calendar chooses the new moon or full moon day as the last day of the month), which overlaps with August/September . 
It is an important festival particularly to the Vaishnavism tradition of Hinduism. Dances of the life of Krishna according to the "Bhagavata Purana" (such as Rasa lila or Krishna Lila), devotional singing at midnight when Krishna was born, fasting ("upavasa"), a night vigil (ratri "jagaran"), and a festival (mahotsava) on the following day are a part of the Janmashtami celebrations. It is celebrated throughout India.
Krishna Janmashtami is followed by the festival Nandotsav, which celebrates the occasion when Nanda Maharaj, father of Krishna, distributed gifts to the villagers of Vrindavan in honour of the birth.