Where can you buy a disco light Those lights in the skating rink A big round ball looks like Epcots energy exhibit?

They are "Disc Balls". Made of mirrors and hung from above the dance floor they had a small motor that turns the ball. Spot Lights are pointed at the ball and bounce off to the floor and walls around the dance floor. Amazon sell them - There are more sophisticated types that have coloured lights on a small gantry around the ball which move through the vertical and horizontal giving greater changes to the light effect.