I have never been much interested in money, other than wondering how much I could safely spend at any given time. And that may be quite obvious, if everybody but me knows these two terms: specie money, and fiat money. The site I found them on is both clear and interesting; I clicked all over the place, and the only disappointment I had was that the specie money link wasn't there yet. So, if you're looking for something to pass the time, try
http://en.wikipedia.org/wiki/British_Banknotes