According to wikipedia it was the first World War that brought the wrist watch into wide use. Only sixty years later people tought that it would be a brilliant idea to have a calculator in your wrist watch. As brilliant as having a PDA or a camera in your cell phone I suppose.
Before the were pocket calculators there were slide rules. I did like them. Thinking about it, I should get one. Or even better: create one with megabytes, megabit etc scales. Having the common technologies like USB2 etc marked. OK, neat, but obsolete in about a year. Still, it would be fun to wip out a slide scale in a meeting when asked how long xyz would take. Actually I am pretty convinced now that I want a slide scale. Good thing my dad tought me how to use one.
In 1962 the DoD came up with a slide scale to compute the impact of nuclear bombs. Somehow I could see Kennedy operating one of these after a brief introduction. Now imagine your job would be to teach George W. Bush to operate and use this device.
The scary part about this is, that both people have the power to push the same button. People then were fast to say that Mr B. had so many great advisors. Those that gave him that darn good intelligence.