This very cool image is from Bad Astronomy. This is astronomers catching a 5 minute X-ray burst at the very beginning of a supernova. That is serendipity of the highest order. The astronomer in question was actually observing another supernova which occurred about a month ago and happened to catch this one. She leapt into action (no doubt after doing a small victory dance) and got a goodly proportion of the world's instruments pointing at it. She confirmed it really was a supernova and everyone got a heap of rather unique data. Very, very cool.
Thanks to Hoyden About Town for posting it somewhere I would see it!