Through the 2008 Summer Games, the U.S. has never won a medal in handball, table tennis, rhythmic gymnastics, and badminton. According to the olympic website, the US has 3 events it has never won a medal in----I know one of them is Handball, but do not know the other two. Through the 2006 Winter Games, the U.S. has never won a medal in biathlon and nordic combined.
The circle with the arrow means male, and the circle with the plus sign means female. the circle with a plus-sign is used as the zodiacal symbol for the planet Venus. It is the female and male sign. the one in your question with the top pointing up is male, and the one with the cross pointing down, is female.
The Circle A is said to represent Proudhon s maxim that Anarchy is Order. (The A is for anarchy and the circle is either a symbol of order or represents the O.) But the Circle A is also said to be a symbol of unity and determination, forwarding the anarchist ideals and the inevitable rebellion against the rulers.