Supernova!

Currently making its way all over the net is the discovery of a "type Ia" supernova only 21 million light years away - what makes this special is that it was found within a few hours of a star (or possibly stars - a Hubble picture shows two red giants very close to each other) exploding.

The Bad Astronomy blog has an update and pictures: M101 supernova update

 and here's the article from Sky and Telescope: Supernova Erupts in Pinwheel Galaxy

But credit goes to The Palomar Transient Factory for the discovery which according to their website: The Palomar Transient Factory (PTF) is a fully-automated, wide-field survey aimed at a systematic exploration of the optical transient sky.

The Supernove is  located in the Pinwheel Galaxy and should be visible to a small telescope in about a week.