You are stuck in a room with two doors. One leads to certain death and the other leads to safety. Each door is guarded by a guard that either tells the truth or always tells a lie, but you don't know which. And they only answer questions with "yes" or "no". You can only ask one question to determine which door leads to safety.
What is the question that you need to ask?
(please note, you cannot maim, disable, kill, or distract the guards in any way)
which of these doors lead to safety? *holds 20 dollar bill* neither door?
I'd ask them if their dead. o.o
If they say "yes" then their the lying one...
If they say "no" then their the truthfuil one...
...and then I'd ask one of them which one of the doors lead to safety and take the approppriate course of action.
EDIT: DAMN, I forgot I can only ask one question.
"Which way to the bathroom?"
"Does this door lead to safety and are you alive?"
Truth sayer in front of safe door would say yes.
Truth sayer in front of danger door couldn't respond because it'd be a no/yes conflict.
Liar in front of safety door would say no.
Liar in front of danger door couldn't respond because it'd be a no/yes conflict.
If you ask that question you should escape. Whichever guard says No, use the other guard. Whichever guard says Yes, use him.
CT was a magical inspiration but I decided to combine the two question phrased as one 8O.
I would use the power of the internets to find the answer to such a riddle the spoil it for everyone 
Push either guard into the door behind him. Since he cannot be harmed, if it is the safe door, he'll be fine, if it's the danger door, he'll bounce off.
Bub linked the correct answer in chat...
Quote:
Ask either guard, "If I asked the other guy if this door you are guarding is the door to freedom, would he say yes?" If you get a "no" answer, it is safe to use the door. Here's why:
* You might have talked to the LIAR guarding the door to FREEDOM. If so, you would get a "no" answer, since the other guard, the truth-teller, would say yes, so the liar you are talking to would say no.
* If you were talking to the TRUTH-TELLER guarding the door to FREEDOM, you would also get a "no" answer, since the other guard, the liar would say "no" and the guard you were talking to would truthfully report this to you.
* If you were talking to the LIAR guarding the door to DEATH, you would get a "yes" answer.
* If you were talking to the TRUTH-TELLER guarding the door to DEATH, you would also get a "yes" answer.
Pach's answer was "Would you be willing to go through this door and does the other guard always lie?"
I had originally thought to change Pach's to "Would you and would he?" but that yields the exact same answers...
What if the person who told you only one guard lies was a liar himself?
Then you thow HIM through a door.
I swear I saw that episode of Yu-Gi-Oh.
All I have in my mind is David Bowie and tight pants...
Also that one scene in 10th Kingdom with the frog. I'd link to a video of it but my youtube-fu is weak.
E: lol html
lol @ Nuch... I might print that up for extra extra credit
I remember something like this on Samurai Jack =D
It's a coomon riddle - but yes, The 10th Kingdom's spin on it put a fresh twis into a tired formula (although I won't spoil it by saying why...).
the Samurai Jack one was funnier because both lied. XD
I find it worrying that I read through the answer to this over and over and it just serves to confuse me more and more.
Maybe I am too tired.
Though this does remind me of a question posed to the player at the beginning of Baldurs Gate 2 - though that one had no right answer and was just to see how you would respond.
Ah, Labyrinth...
Although I think a Pratchett book had the best answer involving something along the lines of "and by the way, whichever door you pick, *you're* going through first!"
Sometimes rephrasing it helps, CJ. *ponders* Actually, it's really difficult to phrase! How about:
Option A) You're asking the liar. The other guy is therefore the guy who tells the truth. You ask the liar which door would the other guy recommend. So the liar would tell you the door, which you wouldn't go through - because he'd lie about what the truthful guy would say.
Option B) You're talking to the truthful guy. If you ask him which door the other dude would recommend, he'll tell you the truth. Since the other guy is a liar, the other guy would recommend the wrong door. So you go through the other one.
Either way, you go through whichever door the guard doesn't recommend.
And Sarah chose the right door - she just chose to continue down when she should have chosen up and hence ended up in an oubliette in the middle of nowhere. Hoggle to the rescue!
DW
PS No, I haven't seen Labyrinth loads of times, why do you ask? 
I THINK I get it a little bit easier now...
I may need a diagram of my own to get it more.
I don't see how I am finding it so hard though x.x
Actually, interesting that you ask that question here at the MF. That same situation showed up in Sonic: In Your Face. Sally faced a two-headed dragon with the same dilemma.
And the hedgehog and his princess bring everything full circle... aah...
SONIC x AMY forevah! 
Sonic doesn't like Amy. o.o Romantically. Rouge either. The 'hog's gay.
