Rube-Goldberg Type Random Number Generators?

stercor asks: "I've been considering random number generators made with easily-available materials. Living in Oregon might suggest photoelectric cells and rain. Or something to do with slugs (generation rate IS a factor, however) My question is what other off-the-wall shelf hare-brained brilliant ideas can other Slashdot readers come up with? Please limit ideas to ones that would actually work." When I was younger, I was always intrigued by the rigs used by most State Lotteries. You know the ones: dump balls into a chamber, throw in a fan/vacuum combination to agitate the balls and to allow a random one to shoot thru a tube when the button was pressed (basically, a high tech version of your average BINGO machine). Has anyone else seen or built a contraption that does something similar but in a weird, roundabout or weird and roundabout way?