Yeah, it's on the tip of your tongue, isn't it? You can see the movie or TV show, remember the look, remember that you really enjoyed it... and the name just escapes you.
I know that there are actually a lot more, but for many years I can recall three titles -- two movies and a TV series -- which bugged me because I could never remember what they were called. The first movie turned out to be called The Forbin Project or Colossus: The Forbin Project (1970). I got that one because I accidentally stumbled onto a copy of Dennis Feltham Jones' novel Colossus. As a kid growing up in the latter decades of the Cold War, this movie creeped me out -- between Colossus (Unity, actually) and HAL, you can get a real complex about letting computers take control, believe you me -- and I loved it. Though I didn't understand why, if you were sealing the computer inside a mountain vault, that you needed to keep the overhead fluorescent lights on inside...
Of course, Hollywood never leaves anything alone:
Imagine Entertainment and Universal Studios confirmed that a remake titled Colossus, to be directed by Ron Howard, would be in production as of April 2007, but seems to have ended up in development hell.
The second dogged me for years, until I rediscovered The Champions in May 2007.
The third? Yet another big budget British SF-ish thriller, this one about a code breaking organization which hired only women, much as women were early "computers" in the math and science fields of the early and mid 20th century. The first third or half the movie was always the most fun, though the ending was interesting -- I can recall ABC or someone running this on Saturday Night At The Movies several times during those junior high and high school years when we rarely went to movies in the movie theatre, and I doggedly took it as a personal feature of mine that "I watched movies for free" when they came out on TV six months or so after their initial release. College changed that, of course.
So today I thought I'd take another crack at it -- and Googled "british code breaking baby rattle". And lo and behold, the third hit was for Sebastian (1968). That's IT!
Alas, there seems to be no evidence that it ever showed up in VHS or DVD, and as a one-word title, it doesn't seem to show up on Amazon, so I can't click on it to be notified if it ever comes out on DVD. So I'll have to languish in despair at having found it, but not found it, here in June of 2010.
Of course, I don't know how it will hold up. It was somewhat sexist even in 1968, though the characters tolerated the divide with some humor. And the "scandal" in the middle, as well as The President's Analyst type LSD drugging by bad elements, were weird and out of touch even when I saw it around 1970. (grin) But the concept of the code breaking, somewhere in between Enigma and NCIS hacking, is a small window into the world of professional puzzles. Indeed, the code at the end, the one which required the baby rattle to crack, always struck me as bittersweet, because it heralded the end to the paper and pencil and letter frequency and analysis code breaking. So much for the intro to codes from my Cub Scout merit badge days and the Encyclopedia Britannica. (sigh) Yeah, I was overly smart for my age in junior high. (smart grin)