From the Mars Today page, this beautiful picture of a meandering water channel at the base of a ridgeline. The interpretation on the Mars Today page says that the water must have been released multiple times over a long period, as the main channel and some craters show visible subsequent erosion. If you want to see evidence of life, you'd want to be turning rocks over right here in the base of the arroyo for biofilm fossils.
Also, the European mars orbiter will begin unfurling its radar booms over the next two weeks. This maneuver had been delayed for more than a year because of fears that it would damage other instruments. The ground-penetrating radar will allow the orbiter to detect subsurface water.
My eyes always optically invert these grayscale images, so that my first perception on seeing the craters is always to see little humps. I guess it should be random which percept comes first, "inny" or "outy" but I do it 100% wrong.