Quote - ... somebody could completely miss a planet

Or not, as the case may be -> http://www.cnn.com/TECH/space/9909/30/mars.metric/

I remember the debacle over the Pentium FDIV bug (due to Intel's initial stance) -> http://en.wikipedia.org/wiki/Pentium_FDIV_bug

There are a few other "urban legend" type tales that I know of involving poor math coding, the one that springs most readily to mind is of F16's crossing of the Equator, they started flying upside down, but fortunately this was spotted during simulator trials.