John von Neumann (1903-1957): an Hungarian-American mathematician who made important contributions of remarkable breadth, including to quantum physics, set theory, computer science, and many other fields. He is the father of game theory and devised the von Neumann architecture used in all modern computers. He also studied cellular automata in order to construct the first examples of self-replicating automata. The term von Neumann machine has been used to refer to both the computer architecture he devised and to an artificial construct capable of reproducing itself.
Von Neumann had a mind of great ingenuity, nearly total recall of what he'd learned, and a great love of jokes and humor.