Lincoln penny as a calibration target
One of the cameras on the rover now on its way to Mars has a calibration target attached that the Principal Investigator thinks will help people understand what they are looking at in the hoped-for imagery. In addition to a standard calibration target and color samples, the camera will show a Lincoln penny for scale and color reference. The penny is from 1909 and represents the first issue of Lincoln pennies, made in the centennial year of Abe's birth.
COMMENT: Cool idea. We often say the space program has to pinch pennies, and here is the literal proof of that - but I think the concept of showing something everyone is familiar with alongside the close views of Martian rocks is a very good one.