Bubble

A huge dome-like construction, made of a vinyl-like material, that is used to convert outdoor courts into ones that can be used in the winter and in bad weather. Blown up and help up (like a bubble) by air pressure, and anchored to the ground, it can effectively cover one or more courts, depending upon its size. It is essential to have a good air-pressure machine that keeps the bubble standing, and back-up machine as well in case the basic one conks out. Otherwise, like the walls of Jericho, the whole thing may come tumbling down.