Ice skating

Ice skating people have shoes will blades. These blades are very sharp (very small area rests on ice) that they create immense pressure (force/area) on the ice surface when they stand over ice. When the pressure is high, the temperature increases and ice melts and forms drops. These drops are very small size that the surface tension can keep it in spherical shape. So they act as if they are some iron balls under the skating blades, which just makes the blade (shoe) to slide over the drops, making the surface almost friction less. So cool huh..!!