Handshakes: Five couples, including the host and his wife, attend a party. Throughout the evening, as introductions are made, various people shake hands (except couples do not shake each others' hands). At the end of the evening, the host discovers that each of the other nine people at the party shook hands a different number of times. How many hands did the host shake, and how many hands his wife shake? 3 Cards: There are 3 cards: one is all red, one is all blue, and the third is blue on one side and red on the other. The cards are shuffled. You pick one at random and it is blue on the side facing you. What are the odds that it is also blue on the other side? Five Hats: Three wise men are lined up in single file, each wearing a white hat. They know there were 5 hats total, three white, and two black, but they can only see the hats on the men in front of them. They don't speak unless they figure out what color hat they have on. Who figures out first? 100 Switches: Yo