One solution is to roll actual dice. GamesByEmail.com uses The Dice-O-Matic to do just that: dice are rolled over a ramp and then scooped up to be transported to the top of the ramp. Halfway, a camera takes a picture of the dice and through some OCR-like magic, the outcome of these real dice rolls is determined.
It's impressive -- 1.3 million dice rolls don't happen all by themselves. Check the video, it's pretty cool.
But it is an over-engineered solution to a simple problem. Using the Open Random Bit, real randomness can be generated with a much smaller footprint. An 8-pin IC and a single resistor for the ORB, a 6-pin IC to drive the ORB and pass the info to the PC through USB, and you're done!
If it's good enough to use in the IFF-system of jet fighter planes and in licensed gambling machines, it's surely good enough for GamesByEmail.com. And I'm sure you can get more than 1.3 million simulated die rolls per day that way. And you can simulate other dice too!
I'm wondering whether there'd be a market for a USB-powered randomness generator...