HiRISE, the High Resolution Imaging Science Experiment camera, which by the looks of it is one hell of a successful experiment (resolution quality gets measured in inches per pixel). Soon NASA is taking suggestions from the general public on areas of Mars to be shot next. Have your selections ready, my nerd brethren.
Photos from Boston.com
New Images from HiRISE's developers at their blog
NASA's project page
HiRISE on wikipedia