Theatre Arts is really an umbrella term for 2 events, Cabaret and Thearical Dance (which by itself is sometimes called Theatre Arts). Cabaret is the event you are probably most familiar with. Couples perform solo to their own choice of music, doing any type of movement - in fact, the lady may be off the floor the entire time! Essentially, the only limitations are that the routine can not exceed 4 minutes (for professionals), and props can not be set up on the floor before the routine commences. Theatrical Dance is I believe only competed at USDSC. It is done to a specified edited piece of music, and multiple couples are on the floor, in heats as in the other ballroom events. Most of the dancing must be recognizable ballroom steps to the music being played. This is still slightly different from the new Showdance category, which must be recognizable ballroom dancing with up to 2 lifts, not to exceed 30 seconds total (if memory serves), but couples perform solo to music of their own choosing.