Ekadasi is an important fasting day dedicated to Lord Vishnu. Usually there are two Ekadasi in month but in May 2008, there are three Ekadashis. The first Ekadashi is on May 1 (In some regional calendars, it ends on May 2). Another one is on May 15 and another on May 31.
It must be noted here that the three Ekadasi in a month is based on the English calendar system.
The Ekadasi fast is usually observed by Lord Vishnu devotees and rice is avoided on the day.
The Ekadasi on May 1 is known as Varuthini Ekadashi.
Mohini Ekadashi is on May 15.
Apara Ekadashi is on May 31.