Just before death you are granted one truthful, understandable answer to one question. What would you want to know?
Obviously a hypothetical scenario. There is no way to pass on the knowledge to anyone else. Time freezes for you only, and once you have your answer you are out of this world.
The question can allow you to see into the past, present and future and gain comprehension of any topic/issue. But it's only one question.
Edit: the point isn't "how to cheat death". You can't. Your body is frozen and there is nothing you can do with this knowledge other than knowing it, and die. So if you would rather be frozen in a limbo just thinking of numbers for eternity, be my guest.
Such a variety of replies, it's been really interesting to read them!
What would you want to know? Personally I'd want to see a timelapse or milestone glimpses of humanity's future until the end of Earth's existence (if we survive that long)
Well, we can prove that a system of axioms can never be both consistent and complete. So for the former, I'd wager not. Would be better to directly ask for it instead, so you get it by fiat at least.
For the latter? I'd wager I'd rather not think about it. What if we found our purpose circa 1300 BCE and have actually had it ever since? I don't think I'd want to risk knowing that :D