Anyone interested in the history of science will be interested in this article: http://www.csmonitor.com/Science/2012/0117/Scientists-find-lost-Darwin-fossils-in-gloomy-corner-of-British-Geological-Survey.
They found Darwin's specimens...shoved away in a dusty corner where nobody went very often.
Thing is, this kind of thing happens all the time, whether it's somebody going through an old VCR collection and discovering one of the erased Doctor Who episodes, or Antiques Roadshow finding a lost master (Which has happened more than once).
I think the message is to keep your eyes open, observe, and open your mind to what you might discover. You never know what it might be worth.