National Cryptologic Museum

Adjacent to the NSA headquarters in Maryland, USA is the National Cryptologic Museum, a museum of cryptology and NSA history open to the public. It's surely second only to Bletchley Park as the ultimate day out for crypto geeks (if geeks had days out, that is).

Regrettably, I've not had chance to visit -- it's a bit of a trek from the UK -- but the next best thing is a superb set of photos posted to Flickr by Austin Mills which document a large proportion of the museum's exhibits. The photos are high enough resolution to be able to read the captions and see the details of the various machines.