Recently a driver has been released for the Raspberry Pi that enables the hardware random number generator on the Pi’s processor. The numbers are generated by tiny thermal fluctuations in the processor. On the linux side after the driver is loaded a new /dev node appears. Once installing the rng-tools rngd it will seed your /dev/random with entropy from the hardware random number generator.
Some cool things are to visualize your random data, or to listen to it. Check out the article or complete instructions and a little theory.