Von Neumann published his first major paper at age 17, and then attended two universities at the same time, in Zurich and Budapest. The latter he attended for a week at the end of each term, to take the examinations. It seems almost as an afterthought that he got a PhD at age 23.
G. Dyson writes in *Turing's Cathedral* that during the oral examination: ". . . David Hilbert was reported to have asked a single question: 'In all my years I have never seen such beautiful evening clothes: pray, who is the candidate’s tailor?'" - Jed
