For fans of mechanical calculators, this is a must-see.  The Computer History Museum in Mountain View currently has a working copy of Charles Babbage’s difference engine on display.  This is a calculator designed in the 1850s but never build until this century.  The machine weighs over 8 tons and has thousands of moving parts.  It can be set up to generate logarithms or other mathematical functions and it even has a printer.  Pretty sophisticated for a mathematician who lived in the age of steam.