I came up with a logic puzzle inspired by this xkcd comic. I don't yet have an answer, and I am wondering if anyone can come up with one.
You are in a room with three doors. Two of the doors lead out, but one of them leads to certain death. Each door has a guard holding a spear stationed in front of it. One of the guards always lies, one always tells the truth, and the third guard will fatally stab you if you ask a tricky question. If the question isn't tricky, he will tell the truth.
For this puzzle, "tricky question" is a question that is:
A "meta-question" about the guards.
Example: "If I asked Guard X about topic Y, what would he say?"
A question that asks about a hypothetical situation.
Example: "If I asked you about Topic Y, what would you reply if you were a liar?"
Another example: "If there were N doors, and I asked you question X, what would you respond?"