Two doors with two guards - one lies, one tells the truth
You are a inWith-stockholder in a room with 2 doors and 2 guards. One of the doors will guide you to unimaginable wealth and behind the other is a financial disaster waiting to happen--you don't know which is which.
One of the guards always tells the truth and the other always lies. You don't know which one is the truth-teller or the liar either.
You have to choose and open one of these doors, but you can only ask a single question to one of the guards.