Colossus was the world's first stored program electronic computer, built during WWII and use to crack the German High Command's Lorenz code. This code was much more complicated than the Enigma code, which Alan Turing cracked using a machine he designed called the Bombe.
Tommy Flowers, a Post Office engineer designed Colossus, which was a physical instantiation of Turing's Universal Machine. By the end of the war 10 Colossi were in use at Bletchley Park. Enthusiasts have built a replica, which has 2,500 valves some of which date to the 1940s. You can see the Colossus at the National Museum of Computing at Bletchley Park and now you can sponsor a valve; £10 is the minimum amount. The Universal Machine has just sponsored a valve, so why not get involved as well - what a great way of being involved with a piece of computing history!
This is the sponsorship URL: http://www.colossusonline.com/index.php