Brain Games to get you going

I enjoy games that keep the mind going, like bubble braker, solitaire, suduko etc

HERE'S A FEW LINKS TO keep you busy and going

http://www.sharpbrains.com/teasers/brain-games-and-teasers-top-50/

http://www.brain-fun.com/


QUESTION: There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?