Anant Chaturdashi puja falls on the 14th day of Bhadrapad shukla paksha (first fortnight) of the Hindu calender year.
Anant Chaturdashi has two main significances. The first is that it is the day of the immersion of Ganapati (also called Ganapati Visarjan). Thus Lord Ganesha is given farewell, only to be welcomed the next year with equal excitement.
The second significance is that this puja is basically that of Shri Vishnu or Shri Krishna Puja. On this day people recite and listen to the stories and legends of God Vishnu who is Anant, the infinite and recite hymns from the Vedas. This is sometimes also called Ananta Vrat. It is an expanded form of the Satyanarayana Puja.
This pooja consists of Yamuna (river) puja, shesha (cobra) Puja and Anant Puja. The water kalash (pot) is assumed to be yamuna, cobra made of grass is Shesha and Anant consists of 14 knotted threads.
For the puja 14 items are of relevance – 14 flowers, 14 fresh and dry fruits separately, 14 leaves of various trees. Even the food prepared and offered to God as prasad consists of 14 vegetables. Legend has it that this puja was mentioned about by Lord Shri Krishna to Pandavas after their defeat by Kauravas. It further tells about a sage Koundinya who went everywhere in search of Shri Anant. He had to undergo much agony and came across mysterious events before Shri Anant gave him Darshan. By performing this puja, it is believed that a person is relieved of all sins committed during his lifetime.
In 2013, Anantha Chaturdashi falls on Wednesday the 18th of September. Anantha Chaturdashi puja is now available in multiple Indian scripts (Thanks to Aksharamukha transliterator). Please see the links below for the pdf file of your choice:
The Panchang details are available at the Puja Calendar page http://mantraaonline.com/satsangh-calendar/ – Please update your files accordingly.