This website I came across called tylervigen.com and the spurious correlations is just awesome at showing that correlation does not necessarily translate into causation. Well unless you want to believe that US spending on science and technology leads to increase in suicides by hanging and suffocation.
Then again after watching that Hollywood snuff film about the rapture, i.e. Left Behind, I could believe that the number of people who drown in pools could be correlated with films Nick Cage appears in.
Or what about the number of Japanese cars on the market which correlates with suicides by crashing of motor vehicles.
Link this website, and when you meet a theist who does not just understand that correlation does not equal causation, send them the link. Thanks to Tyler for creating an amusing resource to teach a simple but sometimes difficult to understand concept.
Oh, and if you made it this far and still do not understand. Think about it this way. Two things may be correlated, yet they have zero impact (causation) on each other. As such if something is correlated, it does not mean the one causes the other.