"Championship Ballroom Dancing" is the only regularly scheduled national broadcast of ballroom dancing in the U.S. It's an annual televising of the Ohio Star Ball, a ballroom competition held each November in Columbus, Ohio. Think of it as the unofficial North American championship. The show consists of the professional int'l style standard and Latin finals (see below for an explanation of international style versus American), and typically also includes cabaret events, and sometimes competitor interviews and/or American style demos. Lately, it's been hosted by dancer/actress Juliet Prowse and seven time U.S. int'l Latin champ Ron Montez.
The show is broadcast on the Public Broadcast Service (PBS) during the May "sweeps" period and apparently enjoys excellent ratings. Contrary to a persistent rumor, "CBD" is not generally broadcast during "pledge" periods. This information comes directly from Aida Moreno, producer of "CBD," who posted it in February of 1994 and confirmed it privately to Eileen Bauer a year later.
However, because PBS stations have a lot more freedom to set their schedules than do their commercial counterparts, some markets may show "CBD" during pledge periods. It's not common, but it probably happens. In any case, although many markets show it on the default broadcast date -- typically the first or second Wednesday of the month -- not all do. So you'll want to contact your local PBS station to find out the date and time of broadcast in your viewing area.