The birthday of Lord Ganesha is known as Ganesh or Vinayak chaturthi. This year it will be celebrated all over the world on 3rd September 2008, the fourth day of shukla paksha ( the waxing moon period) in the luni-solar month of Bhadrapada (when sidereal sun is in Leo). Typically, the day falls sometime between and August 20th and September 15.
Ganesha is the lord of obstacles and the lord of letters and learning. He is worshiped before starting any work for removal of all obstacles and delays in the way of fulfilling any action in Vedic tradition. His worship brings siddhi, success in undertakings, and buddhi, intelligence.
In addition, this year Ganesh Chaturthi coincides with Sun-Saturn Conjunction in Leo trined by retrograde Jupiter from Sagittarius, according to sidereal Vedic astrology. This planetary combination is of special importance to those born with sign Leo as ascendant, sun sign or moon sign (janma rasi) in their Indian horoscope.