Pop-up books and cards have been around since the 18th century, and recently have seen a surge in popularity through the elaborate designs of pop-up masters like Robert Sabuda and Matthew Reinhart. But the most stunning and elegant pop-up effect I have encountered is the Pop-Up Spinner card invented by an anonymous Japanese student. How it functions turns out to depend on a geometric theorem concerning linkages proven in an undergraduate thesis. I will explain the connection and prove the theorem.