Ashadh Purnimka : It is in th emaemory of the first sermon of Buddha containing Mahaparinirawana.
Full Moon of Vaisakha : it is asacred day in buddist calender. it was on this day that prince sidhartha, who later became buddha was born. it was again on this day that buddha got enlightement under a bodhi tree at gaya and again it is on this vishaka purnima, 80 years after that buddha attained mahapariniwana in kosi.
Diwali: Celebrated to coommemorate the of Rama to Ayodhya after 14 years' exile. Celebrated in October-November.
Durga Puja: Celebrated in september-October. It is a national fetival of Bengal which signifies the victory of the good over evil.
Dussehra: Celebrated in Northern India in the month of September-October. It commemorates the victory of rama the good over Ravana(the evil).
Rath Yatra: Celebrated by the followers of Lord Jagannath in the month of june when the Lord is taken out in the chariot procession.
Ganesh Chaturathi:Celebrated in month of august or september in the honour of the Hindu God Ganesh, popular in Western india.
Holi:Celebrated inthe month of march. It marks the advent of spring. I is popularly known as festival of colours.
Janmashtmi: Celebrated all over India as the Birthday of Lord Krishana in august.
Saraswati Puja: Celebrated in the month of january-February in the honour of goddess of learning and fine art-saraswati.
Shivratri: Celebrated on the 14th day of the new moon in March in Honour of Lord Shiva.
Pongal: Celebrated in many parts in south india in january. In the Andhra' Pradesh, it is also known as sanskriti, marks the harvesting of the crops. Newly harvested rice is ceremoniously cooked and partaken by all.
Baisakhi:Celebrated all over Northern India and tamil Naidu in the month of april. The new year day of the samvat(vikrami calender).Guru Gobind singh organised the sikhs into khalsa on this day. Beginning of the Harvesting of crops.
Nag Panchami: Dedicated to the mythical God of Serpents Nag Devta. Celebrated in many parts of Rajasthan and maharashtra snakes are worshipped to obtain immunity snakes bite.
Onam:Celebrated in Kerala. Primarily a harvest festival.