Today, 2 September 2011 is Rishi Panchami Vrat (Rushi Pancham). It is observed on the following day of Ganesh Chaturthi. Rushi Panchami falls on Shukla Paksha Panchami in Bhadrapad month. This vrata is dedicated to Saptarishis or the seven Sages in Hinduism.
In each manvantara there will be seven different Sapta Rishis. Sages Kashyapa, Atri, Vashishta, Vishwamitra, Gautama, Jamadagni & Bharadwaja are the Saptarishis for this seventh Manvantara (the interval of Vaivasvata Manu).
Here is the Rishi Panchami Vrat procedure, Rushi Panchami Puja Vidhi