The Mars Science Laboratory rover, aka Curiosity, is currently in its 102nd sol (Mars day) since landing. As it takes pictures with its 17 different cameras the images are released on NASA's raw images website, often within hours of when they were taken.
Here's a random sampling of some recent images--over 25,000 have come down to date--followed by an appeal by Neil deGrasse Tyson.
Self portrait of the main mast:
Alpha proton x-ray spectrometer (APXS):
Sample analysis scoop:
Sand grains via MAHLI, microscopic hand-lens imager:
Detail of above:
MAHLI self portrait:
Neil deGrasse Tyson's "one cent for NASA" proposal:
Check this website to browse the latest images downloaded from Curiosity: