Skanda Sashti the sixth day in the bright half of the Tamil month of Aippasi is celebrated all over Tamilnadu especially in temples dedicated to Subrahmanya commemorating the destruction of evil by Kartikeya.
Skanda is an ancient deity mentioned in inscriptions and in the Mahabharatha, Śiva Purana and Kalidasa's Kumara Sambhavam. 
The Story of Skanda Shasti is the story of the birth of Skanda or Kumara. Lord Brahma said " only the spark of Shiva can produce the hero who will defeat evil". Shiva was lost in a deep state of meditation and none dared to disturb him.On Brahma's suggestion, they sought the help of Parvathi and Kama (the god of love). Parvathi engaged herself in severe penance and Kama engaged himself in the Surasamhara,a suicidal mission of arousing Shiva from His state of Samadhi. Kama shot his arrows of love at Shiva who was eventually disturbed and the fire of anger from his third eye burnt Kama into ashes.The penance of Parvathi and the sacrifice of Kama paid off and Shiva was aroused from his Samadhi. None could bear the sparks of His fiery seed which fell into the mouth of Agni, and received by Ganga, who in turn threw it into Sara Vana and thus Saravanabava was born, also called Skanda - Shiva's power of chastity preserved through penance.Skanda was raised by the six mothers of the divine constellation of Krithika. Karthikeya divided himself into six babies to be nursed by six mothers. When Parvathi came and gathered all the six babies, He became Shanmukha - the one with the six faces and one body.Shanmukha became Kumara - the powerful virile adolescent who was also the beautiful and the handsome (Muruga) . He was made the General (Deva Senapathi) of God's army.  Skanda received from his mother Shakthi an all powerful Vel (lance) and hence is also called Sakthi Velan. He engaged the armies of Simhamukha, Surapadman and Tarakasura in a six day battle and vanquished all of them on the sixth day. The Asuras were annihilated and the Devas were liberated. Therefore the sixth day (Sashti) of the waxing moon (sukhla) in the month of Ashada (Oct/Nov) is celebrated as Skanda Sashti.
Corresponding to the six days of war over evil, devotees undertake fasts, prayers and devotional singing to Lord Muruga. 

PARTICIPATE IN THE SUBRAHMANYA HOMAM AND GANAPATHY HOMAM