Pseudo-random using shift registers with EXOR feedback . http://www.ee.iitb.ac.in/student/~shalini/ESD_EE616/course_project.pdf
Depending on what you want it for.. use google images to find white noise generator. I know it's not in the spirit of the question but if you were building some sort of networked device you might be able to get your random numbers from a web site like this.. http://www.random.org/
Gambling machines use fluctuating dark currents to generate random seeds for a pseudorandom number generators. random.org also a source of random numbers. Claude.
