If you know what Cup Stacking is, you're probably a parent or a kid who graduated recently. Speed stacks have been around for more than 18 years, but it's blowing up in a big way. Not only has sport ...

Editor’s note: This segment was rebroadcast on Sept. 30, 2025. Click here for that audio. In the early 2000s, thousands of U.S. schools had their students race the clock to stack cups in gym class.