A few weeks ago I linked to this graphic from Bloomburg, purporting to show all sorts of strange relationships such as that the U.S. housing bubble was caused by too many babies named "Ava."
The real message, of course, was to beware of statistical correlations: just because two things appear to be correlated does not mean that one causes the other or that they are even related. If you look deeply enough you can always find some bogus way to correlate two statistics.
I was remiss, however, to not link to the classic chart from 2007 purporting to show that pirates prevent global warming. Since the corelation-is-not-causation message can't be repeated too often, I'm linking to it today.