So I often go on about how you learn to notice what you can and cannot trust on Wikipedia, that articles on controversial or obscure topics may be less trustworthy, but that articles on argon or something are probably more trustworthy, because people rarely bother to vandalize that stuff.
Well, Saheli has found an example of the latter. Take a look at this diff. Someone in Ecuador (according to reverse IP lookup) decided to change all the numbers on a table of gravitational acceleration at different major cities. Wha-huh?! Why would someone do that? I guess it only takes a few. :P