Website with TCS Fun Facts
Here are some interesting anecdotes about TCS giants. Some of them are dark, quite possibly the opposite of 'fun', but you also might get something you're looking for. This also might work best as a community wiki.

Kurt Gödel:


Gödel was concerned with developing a mathematical framework for describing the effectively computable. Both he and Alonzo Church developed candidate frameworks (Recursion and Lambda Calculus respectively), but neither satisfied him. In fact, Gödel acted very much as the ultimate skeptic - no proposal which satisfied all of his contemporaries seemed to satisfy him. He involuntarily became the de facto litmus test for effective computation. Alan Turing's A-Machines (we later began to call these Turing Machines...) were the first idea to satisfy Gödel, and this launched a lot of the original interest in Turing's paper. Curiously, Gödel later wished to revoke his support but things were already set in motion.
Gödel was a good friend of Einstein. In fact, they purportedly walked together often when they were both at Princeton. Supposedly Einstein once made a comment to a colleague implying his work meant very little to him; that the reason he chose to stay at Princeton was for his walks with Gödel.
He purported to have a proof that God exists.
Gödel was a very suspicious individual. His own work in Physics and Philosophy convinced him that work of Leibniz was suppressed by a conspiracy against him despite a lack of any solid evidence. In his later years he became increasingly frightened of being poisoned to death and would only eat food his wife taste-tested for him. At one point his wife became hospitalized for an elongated period, during which time he was afraid to eat anything and starved himself to death. It's interesting, but perhaps not fruitful, to speculate about Turing's suicide by poison and what role this may have played in Gödel's conspiracy theory.


Alan Turing:


The "Father of Computer Science". Turing's original work involved describing mathematically what we should think of as effective computation. Right before publication, having just learned of the lambda calculus of Alonzo Church, he scrawled down a proof which showed equivalence between his machines and Church's calculus.
Turing was a student of Bertrand Russel and also a Philosophy student of Wittgenstein. I believe I have heard Turing became very frustrated at his inability to penetrate Wittgenstein's philosophy and eventually retreated from the subject.
He is considered a war hero. Turing's machines, and in particular his modifications to the Bombe, helped the Bletchey Park code breaking effort in WWII to crack the German Enigma machines.
Because Turing was a homosexual and also likely because of his once high security clearance, the British Government striped him of his status and forced him to undergo extreme hormone treatment. Due to this persecution and other factors Turing commit suicide, by consuming an apple he had laced with cyanide. There is speculation as to why Turing chose to commit suicide this way. The British Government just recently released a formal apology for their actions, 70 years later.


John Von Neumann:


With influences well beyond Computer Science, Von Neumann may have been the last well known poly-mathematician. His work helped to develop quantum physics, game theory, theoretical computer science, PDEs, microscopy, systems architecture, functional analysis and more.
Von Neumann was entirely unimpressed by John Nash's seminal contributions to Game Theory. Von Neumann is reported to have shrugged and said, "[Nash Equilibrium] is just a fixed point theorem."
Von Neumann was known for his terrible driving. Supposedly the cause of many of his car accidents was the fact he insisted on reading at the wheel.
Unlike many other scientists in the Manhattan Project, including Einstein, who would later come to regret their involvement in the project and actively protested nuclear programs/stockpiling, John Von Neumann never had any regrets. He continued to work on the nuclear proliferation of the United States for some time.