The Colossus computer would be my guess. (Score 2, Interesting)

The Colossus machines were electronic computing devices used by British codebreakers to read encrypted German messages during World War II. These were the world's first programmable (if not fully), digital, electronic, computing devices. They used vacuum tubes (thermionic valves) to perform the calculations. http://en.wikipedia.org/wiki/Colossus_computer And it still runs (at a museum)