One the first and second laws of supply and demand. Or why we shouldn't be freaking out about markets.
How about a list of famous errors made by economists? Worth pointing out that a hypothesis struck down by an ugly fact subsequently being rejected as a hypothesis is one of the marks of the scientific method.
10% of HMRC's records are wrong. Bodes well for the ID card system, doesn't it? And shy is such a computer system so darn expensive?
Things you shouldn't do (but which people have done) when looking for a job as an economist.