The reason I've gone very quiet of late is that two weeks ago I visited Bletchley Park, and was so fascinated by the details of the cryptanalysis of Enigma that I've spent every spare moment since working out the crib/bombe technique, and implementing software simulations to verify my understanding.
I had what I think was a working bombe simulator by last weekend, but running in ruby on my netbook, it was somewhat slower (for a moderately complex menu) than the 1942 electromechanical version. Not having the resources of a state war machine to draw on, that makes it a bit too time-consuming to actually test the process. Every optimisation I attempted made it slower, so I have resorted to a C++ port of my ruby code, which is not yet complete.
(I am aware that many simulators already exist - the point of my simulator is to demonstrate to myself that I know how it is supposed to work).
There's loads of important stuff to write about, but I just can't put this down right now.