874
xkcd #2897: Light Leap Years
(imgs.xkcd.com)
Alt text:
When Pope Gregory XIII briefly shortened the light-year in 1582, it led to navigational chaos and the loss of several Papal starships.
They're hit or miss. This one is mildly amusing to me. It's been going strong 3 comics a week for how many years now? Not all of them are good of course, some I consider just bad but I think most weeks have at least one good one.