SkateSlope

Ice is flat. Or rather, to be pedantic, ice forms a surface parallel to the geoid, an approximate sphere roughly 13,000 kilometers in diameter.  This is true of both ice on rivers and lakes, and also ice in ice rinks.

Making an ice rink is fairly straightforward.  You construct a shallow dish and lay plastic pipes across the bottom.  You fill the dish a few centimeters deep with water, then pump refrigerant through the pipes.

Skateboard parks, in contrast, are anything but flat.  This allows skateboarders the freedom to play with the interchange between their kinetic and potential energy, with - in competent hands (or rather, feet) - spectacular results and  broken bones.

Skateboard parks are made by pouring concrete into formers and letting it set.

But you could do just the same thing with ice.  The formers could contain the refrigerant pipes.  You would fill them with water, not concrete, then turn on the refrigerator.

The result would be like a skateboard park, but for people wearing ice skates.