I was lucky to be sitting in the speaker's corner at 25C3 when the MD5 hackers met before the talk and was asked to take a picture of them.
I quickly set up my newly purchased Strobist gear and caught the following shot:
The uncropped version can be seen over at the CCC events blog, and for those who need it, here is the original version in its complete 12 MP glory. Everything is released under CC-BY, so I am happy if you use it, but please credit me accordingly (»Photo: Alexander Klink.«).
I was not quite happy with this version, but I learned the typical photographer's problem: the subjects only have a limited amount of time. Once we (risktaker, POCsascha and myself) had set up a better version with two flashes and a softbox, they were already on their way to their talk ... :-( — which was awesome, of course.