Ganesha Chaturthi also known as Vinayaka Chaturthi is celebrated as the birthday of  Lord Ganesh. It is among the most celebrated of the festivals in India, and perhaps the only one involving general public (others only involve families and friends and are celebrated privately). 

Story of Ganesha Chaturthi
According to Hindu mythological scriptures Lord Ganesha was formed by Goddess Parvati, wife of Lord Shiva. It is said that one day Parvati formed a sculpture from the paste that she used on her body before taking bath. She infused life in that figure and ordered him to guard the entrance of her bathroom. God Shiva returned and stopped at the entrance of his house by that boy. In extreme rage Shiva struck off the boy's head. This incident filled Parvati in utter grief and requested Shiva to return her son. Then Shiva fixed the head of an elephant and restored life onto the body of that boy. Lord Shiva named this boy as "Ganpati" Gan means (hosts) & Pati means (Chief) and blessed that Ganpati would be worshipped before every new venture. The procession to immerse Ganesha idols/images on Ganesh Chaturthi finds its links with Indian Freedom Struggle. Lokmanya Bal Gangadhar Tilak started Ganpati Visarjan procession in 1893 and used it as a platform to penetrate awareness about the freedom movement among the mass of India.

Significance of Ganesh Chaturthi
"Vakratunda Mahakaya Suryakoti Samaprabha, Nirvighnam Kuru Me Deva Sarvakaryeshhu Sarvada"

"O Ganesha - Ganapati, One with a curved trunk, a large body, and a brilliance equal to a crore suns! O God, please make all my undertakings free from obstacles always."

Ganesha, the lord with elephant head riding on a mouse, is mostly loved God of Hindus worshipped for success (Sidhi) in undertakings, and intelligence (budhi). Ganpati is praised before any venture is started and known as the God of education, knowledge and wisdom, literature, and the fine arts.

Ganesh Chaturthi holds utmost significance among the followers of Lord Ganesha. Lots of preparations are made to celebrate this auspicious Occasions : large public processions, pooja ceremonies, social get together, erection of giant size mandpas and special religious ceremonies are organized. Apart from a big Occasions, Ganesh Chaturthi has also become a very important financial activity. Thousands of artists & small and medium industries eagrly waits for this mega Occasions.