One of the first things you learn in any statistics class is that correlation doesn't imply causation. Nonetheless, it's fun to consider the causal relationships one could infer from these correlations.
Ice cream consumption leads to murder.
Source: badpsychologyblog.org
A pirate shortage caused global warming.
Source: venganza.org
Living in a poor country increases penis size.
Source: nerve.com
Eating organic food causes autism.
Source: boingboing.net