It is unwise to be too sure of one's own wisdom. It is healthy to be reminded that the strongest might weaken and the wisest might err.
-- Mahatma Gandhi (1869 - 1948)
Ganesh Chaturthi or Ganesh Utsav or the birthday of Ganesha (the elephant-headed God of Wisdom and Prosperity) falls on the fourth day of the Hindu month of Bhadrapada (around August-September). It is celebrated all across India and is the biggest festival in Maharashtra. So if you are anywhere close to Mumbai, don’t think twice about moving heaven and earth to be there for Ganesha’s day. It’ll be a day you shall look back upon with some wonder.
Ganesha is the foremost god of the Hindu pantheon. This brave guardian of the door to Parvati’s bath is beheld today as the most auspicious God of new beginnings. He is worshipped during every festival and before people undertake a journey or embark upon a new venture. You will also see him carefully guarding entrances to temples and homes, peeping out of calendars and happily gracing marriages and other such occasions.
More info on Ganesh Chaturthi