Found this through the Bad Astronomy Blog: Best. Image. Ever.
One look at it and I instinctively knew what it was. Almost made me cry. But that's because I'm a geek.
Phoenix descending to the Martian surface underneath its parachute. This incredible shot was taken by the HiRISE camera on board the Mars Reconnaissance Orbiter. You can easily see the ‘chute, the lander (still in its shell) and even the tether lines!
Phil Plait has a moving reflection on the picture. Go read it.