Ganpati Ganesh is the most widely worshipped Hindu God. He is a non-sectarian deity, and Hindus of all denominations invoke him at the beginning of all prayers, important undertakings, and religious ceremonies, as He is considered to be the Lord who removes all obstacles (vighna) and hence is also called Vighneshwara. Ganesh is popularly held to be the son of Lord Shiva and Parvati.
He is known as the Hindu elephant god with an elephant head, four arms. In his upper hands he holds the paash (noose) and ankush. The lower two hands are held in the abhaya and varada mudras. He is also seen holding his broken tusk in his right lower hand and a modak in his left lower hand. He has a huge belly and is fond of various sweets and fruits. He wears a snake as an ornament round his belly. His vahana is a tiny mouse (mooshak).
He is considered to be the lord of eight siddhis and nine nidhis. The Ashta Siddhis are - Anima, Mahima, Garima, Laghima, PrÄpti, PrÄkÄmya, Istva and Vaśtva. The Nav Nidhis are - Padma, Mahapadma, Shankha, Neel, Makara, Kachhapa, Mukund, Kund and Kharva. He is generally regarded as a bachelor, but according to another school of thought, he has two Shaktis - Riddhi & Siddhi. Riddhi represents prosperity, while Siddhi represents success, both attributes of the Goddess Lakshmi.
An annual festival honours Ganpati Ganesh for ten days, starting on Ganesh Chaturthi, which typically falls in late August or early September. The festival begins with people bringing in clay idols of Ganesh, symbolizing Ganesh's visit. The festival culminates on the day of Anant Chaturdashi, when idols of Ganesh are immersed in the nearest body of water, while the people fondly shout "Ganapati Bappa Morya" (Ganesh come back soon next year).
Today, Hindus across India celebrate the Ganapati festival with great fervour, though it is most popular in the state of Maharashtra. The festival assumes huge proportions at the Siddhi Vinayak Temple in Mumbai and Pune and in the surrounding belt of Ashtavinayaka temples.
Chanting the following prayer from Sri Ganapati Atharvasirsa Upanishad (stanza # 8) appeases him :
"Om, Let us meditate on Sri Ganesh, the lord with one tusk. May that great lord with curved elephant trunk inspire and illumine our mind and understanding."