Vaikasi Visakam is the famous festival celebrated in Tamilnadu . It is this day , Lord Murugan , son of Lord Shiva was incarnated in this world to save Earth and to save the Devas , from demons like Soorapadman . The birthday of Lord Muruga falls on the Vaishakam star in the tamil month , Vaikasi (May- June). 
It is also said that Valli - Murugan (Kalyanam ) marriage took place on the same day .
On this day , all devotees visit Lord Murugan temple at Thirupparankundram and Lord Subramaniaswamy temple. Devotees take out procession carrying Milk pots and some take Kavadi on this day . In Houses pooja are done to the idol of lord Muruuga and sakarai Pongal is done as the neivedyam. People read kanda shasti kavacham , Shanmuga kavacham.