[vgm]

Interestingly, Godel gave a presentation somewhere within 5 - 7th September at Koningsberg presenting the first incompleteness theorem. At this time, he did not have the second. [1]

Von Neumann was in attendance and he wrote a letter to Godel on November 20th announcing his discovery of the second incompleteness theorem. As it turns out, Godel had just sent a paper for publication on November 17th with the proof of the second incompleteness theorem. In reply to Godel, finding out he had just been scooped, von Neumann wrote:

"As you have established the theorem on the unprovability of consistency as a natural continuation and deepening of your earlier results, I clearly won't publish on this subject." [2]

[1] http://goo.gl/uJH9Q [2] http://goo.gl/AXfQV

(Links are very long, hence the shortner. They take you to Google Books.)