I'm curious as to what sort of event or discovery would be enough to "prove" the existence of a god to you?
Would it be hearing the god's voice in your head? Would it be an event predicted in some holy book? The god rearranging the stars of a particular galaxy to spell "Yes I'm real" in every known language, as viewed from Earth?
Ok, there have been some pretty creative responses, but I'm going to change the question a little bit now. What would be the LEAST amount of proof that would be required for you to start entertaining the idea that there is a supernatural intelligence at work in the universe?