What's the etymology of the phrase dead rubber? Googling, I see references to diverse sports as well as a reference in attributes it to some obscure bridge reference. I do not understand it.
Edited to add definition from top answer supplied by @Josh61 below:
Dead rubber is a term used in sporting parlance to describe a match in a series where the series result has already been decided by earlier matches. The dead rubber match therefore has no effect on the winner and loser of the series, other than the number of matches won and lost.