When I was little (and had too much free time) I memorized many digits of some transcendental numbers. The only (semi)practical use I've found for that knowledge, is that I can use it as a reasonably good pseudorandom stream. If for some reason I have to choose things pseudorandomly. Pick an arbitrary starting point in pi, and press 'd' for even digits and 'f' for odd digits, I get around 0.49 accuracy with this oracle.
Mm I did something similar, doesn't need memorization though: arbitrarily form sentences, go through the letters in order, and pick 'd' for a-m and 'f' for n-z. Of course there will be some patterns, but it's sufficient for this. And I think this strategy uses more free will :P
I imagined how I would have coded it and so I devised a system to get it down as low as possible. I ended up with 0.44 accuracy. Pure random would have been better :)
That might be a slippery slope though. Is a known random sequence less random than an original one? Should a randomness detector keep a database of all random sequence ever produced to give lower scores to known ones?