Anna Norgren Mahon is the American record-holder in the hammer throw. Don't tell anyone, though. It's a secret. Not only are Mahon and her record largely overlooked, many people don't even know that the hammer is actually a ball - a 9-pound stainless steel ball attached to a 3-foot wire with a handle at the end - and not a carpenter's tool. "I can see how someone might think that," said Mahon, a 28-year- old from Stamford, Conn. "But within our sport, people know a lot about my event, and it's a much bigger deal in Europe. And if [fame and fortune were] what I was looking for, I probably would...