A true random number generator, created by John Walker.

Most random number generators aren't really random. They use clutter that comes from other programs or even a clock, and pre-set algorithms to convert the clutter into a number to something in the range they want. So by knowing the exact circumstances in which the number was generated, it is possible to generate the same number twice (theoretically).

HotBits uses the decay of radioactive material to generate random numbers. They have managed to connect a radioactive substance to a computer to let it pass out the data over the Internet.

The use of this? Well... none, because communication via the Internet is based on encryption using pseudo-random numbers, fixed algorithms or it's just good ole plain communication(there is no secure way to transmit the random data to the user). But it's exceedingly froody, and I hope to see a random data unit in every PC soon.