I have the privilege of serving at the NATO Summit in Chicago this month. From my perspective as a Seattle WTO participant, this version seems significantly more complex. I've learned a lot of new things, and have been able to apply a lot of what I know from working in my civilian jobs.
While I can't go into detail, for obvious reasons, it's definitely an adventure worth having! (That applies as long as everything doesn't go seriously sideways.) If nothing else, I've had an opportunity to visit all of the international airline lounges, plus the super-exclusive World First Class Lounge of a domestic airline...very luxurious! (It's likely the only opportunity I'll ever have to get past the heavily-guarded front desk without getting the bum's rush!)