Inside Elections has an interesting post on the dice that were used to randomly select precincts for manual recount. In a Punchscan election, there is a lot more dice rolling. We need random choices of ballots to audit and sides of the tally to reveal.

Dice have their shortcomings. First, to convince yourself a die is not loaded requires a lot of rolling and statistical number crunching. Second, its fine if you are in the room to witness the rolling of the dice, but the process does disenfranchise everyone who is not.

For these reasons, Punchscan uses stock data to generate random numbers. Getting something random out of the data is a bit tricky (although, unfortunately for investors, not tricky enough) but it results in a random selection that anyone with a newspaper or the internet can check. For more details, see this paper.