I'll start off with a really nice one which I saw in another forum. A group of 10 logical people are stranded on an island. They all each have either blue, green or brown eyes, but the numbers of each are not known. The people are unable to speak or communicate with each other in any way. The only way to get off the island is on a ship which comes every night. The only way to get on the ship is if you can tell the captain with certainty what colour eyes you have; if anyone gets the answer wrong or says anything else other than, "My eye colour is ____", everyone is killed (the Capt. is bit of a douche). The people have all been trapped on the island for some months until one day, the captain gets bored and shouts, "I CAN SEE SOMEBODY WITH BLUE EYES" before he sails away for the day. Everyone on the island hears him. Assume (i) everyone wants to leave the island, (ii) no one is suicidal, (iii) there are no mirrors/reflections, (iv) killing people/eye gouging is a no-no. The question is: WHO LEAVES WHEN? Hint 1: Spoiler There is at least 1 person that gets off the island.