Cuddly Wuddly Tribe
A remote Pacific island is occupied by two tribes: the Cuddly-Wuddlies and the Nasty-Wasties. They are utterly indistinguishable by appearance, but differ completely in their character and live at opposite ends of the island. Cuddly-Wuddlies always tell the truth and are reknowned for their kind hospitality, whereas Nasty-Wasties are infamous for their compulsive lying and cannabilism; being especially partial to the taste of visitors.
By the time you arrive the sun is already setting and being out so late is not a good idea. You stand at a fork in the pathway: one direction heads to the Cuddly-Wuddly village and the other leads to the Nasty-Wasty village. However, you don't know which way to go.
A man is standing nearby and as you are in a hurry you have time to ask one simple question.
What question could you ask to ensure that you receive correct directions to the Cuddly-Wuddly village?
The question is surprisingly simple: "Which way do you live?"
If the man is a Cuddly-Wuddly then he will point to his own village.
If the man is a Nasty-Wasty then he will lie and instead of pointing to his own village he will point to the Cuddly-Wuddly village.
In other words, it doesn't matter which tribe they belong to, either will point to the Cuddly-Wuddly village.
Note: This question will always work with a Cuddly-Wuddly, but it will only work with a Nasty-Wasty if they choose to co-operate with your clever question. If they are as sneaky as they are dishonest then they could say something like, "That way!", pointing back the way you came, which is a blatant lie. In fact, with an unco-operative liar there is no question that you could ever ask to catch them out.
What question could you ask if there were more than two pathways?