Black and white hats
A king wants his daughter to marry the most logical of 3 intelligent princes, and so comes up with a test for them.
The princes are gathered into a room and seated, facing one another, and are shown 2 black hats and 3 white hats. They are blindfolded, and 1 hat is placed on each of their heads, with the remaining hats hidden in a different room.
The king tells them that the first prince to correctly identify the color of his hat will marry his daughter. A wrong guess will mean death.
The blindfolds are then removed. You are one of the princes, you see 2 white hats on the other prince's heads. What color is your hat?