Good Riddles

Question: At school Joe has three friends: Tim, George and Paige. Two of them play football, two play tennis, and two play golf. The friend who doesn't play golf doesn't play tennis and the one who doesn't play football doesn't play golf. Which sports does each person play?

Question: I stand in one place yet I fill a whole room.
I can be filled with molten rock and come in every hue.

What am I?

Question: What can float but can't sink.

Question: Two men are facing each other alone in a large room. There is a clock on the wall. One man, who thinks of himself as a prophet, says to the other, "In five minutes you'll be stabbed in the back."

The other man is very distraught and stares at the clock. After five minutes he is stabbed in the back.

What happened?

Question: 4 people fall out of a boat and only 3 get their hair wet.