Click here for the original audio. Thousands of U.S. schools have their students race the clock to stack cups in gym class. Why? A former circus clown from Colorado named Bob Fox holds the key. Here & ...

Yung-Deng Lin can stack a group of cups in about 1.6 seconds, an impressive time for a 7-year-old. To give an idea of how fast the child can stack cups, the World Sport Stacking Association overall ...