This kind of falls in the interesting things I found while surfing
One of the persistent bits of common health knowledge is the idea that one should drink 8 8-ounce glasses of water every day in order to be healthy (other iterations of this common knowledge say anywhere from 6-10 glasses or more). Another persistent bit of common knowledge is that caffeinated drinks don't count toward that total since they cause dehydration rather than prevent it.
One of the best books that I've read in a long time is Made to Stick by Chip Heath and Dan Heath. Their blog, though not updated regularly, is a regular stopping point for me.
On 15 July, Dan posted a short bit on the 8 x 8 water idea and pronounced it an urban legend, albeit a very sticky one. He pointed to an article in the online journal Slate that reported on a study debunking the idea (this link downloads/opens a PDF file) from the Journal of the American Society of Nephrology, traced the history of the idea, and included a link to a Snopes.com article on the urban legend.
Granted, runners and others who exercise or sweat profusely, need to watch their fluid intake. But, it seems that what we have long taken as absolute truth (8 8-ounce glasses of water per day for everybody) is taken by many to be false -- an urban legend that has persisted for hundreds of years.
Run well, y'all (and hydrate smart),