Let’s Make a Deal
You choose one door — say, number 1 — and the host (who knows what’s behind the doors) opens another door — say number 3 — which has a goat behind it. You’re then allowed to stick with the door you picked, or choose the other one — number 2 in the example.
The question is: should you switch your choice? The answer is simultaneously blindingly simple and fiendishly counterintuitive. But the above video might be your best chance yet at wrapping your head around it. [YouTube]