Today, 4 June 2012 is Purnima vrat, Full Moon in Hindu calendar. It is Jyeshta Purnima and marks the end of Jyeshta Month in North Indian Hindi Panchangas. Jyeshta Purnima is also celebrated as Vat Purnima (Vat Savitri Vrat Purnima), Devsnana Purnima, Eruvaka Pournami, etc..
Purnima begins at 8.18 PM on 3 June and ends at 4.42 PM on 4th June 2012.
The following day of Jyeshta Purnima (5 June 2012) marks the beginning of Ashada Month in North Indian Hindi calendars.
On 4 June 2012, Chandra Grahan (Lunar Eclipse) will be taking place. This grahan will be visible from some places in South India and some places of Central India and almost all the places of West Bengal, Odisha, and North Eastern states of India.