Today, 31 May 2012 is Ekadasi vrat (Nirjala Ekadasi, Pandav Ekadasi, Bhimsani Ekadasi & Bhimsen Ekadasi. It is observed on Shukla Paksha Ekadasi in Jyeshta month. Smarta Ekadasi is on May 31 and Vaishnav or Bhagvat Ekadasi vrat is on June 1.
Nirjala Ekadasi vrat katha or the story associated with Nirjala Ekadasi is mentioned in the Padma Purana.
Kurma Jayanti is also observed on Nirjala Ekadasi in some places..