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). In 2010, Vaikasi visagam falls on 27th of May.
It is also said that Valli - Murugan (Kalyanam ) marriage took place on the same day .
Legend , according to Puranas :
Once Devas were driven out of heaven by demon Surapadman with the help of boons he received from Lord Brahma. when Devas were unable to defeat him , The king of devas , Lord Indra , went to seek the help of Lord Brahma. Lord Brahma was unable to help Devas , as he has given the boon to surapadman , seeing his severe penance ...instead he asked Lord Indra to seek the help of Lord Shiva . Lord Indra narrated the whole story to Lord Shiva , enraged Lord shiva , opened his third eye and the fiery sparks that came from Lord Shiva's eye , turned into six babies . Later Devi Parvati joins all the six babies into one and thus Lord Muruga was incarnated and vanquished the demons .
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