Metal Tippie Top
This spinning top has a surprising behavior. When spun, it will introvert itself to spin upside down until it loses momentum. This unusual gyroscopic effect is general credited to surface friction. This small friction causes a torque which gradually rotates the sphere on a second axis and forces it up onto the stem. This precision tippie top was machined from aluminum to achieve the best effect.
Great tool to demonstrate angular momentum and is a deceivingly tough problem for physics students to figure out.