Trinity Rep’s Appropriate is a sprawling, gut-churning comedy about a white Southern family that refuses to acknowledge its late patriarch’s insidious past. A rounded stage with gauzy curtains lends a distant feel to the first act, a Tennessee Williams-style free-for-all where seven members of an Arkansas clan (plus one hippie girlfriend) take turns revealing how much they can’t stand one another. By the third act, though, the stakes have escalated and the audience seems just as guilty as everyone else. The laughter gets progressively more uncomfortable, and several moments in the play elicited audible gasps. It’s definitely one of the more challenging shows I’ve ever seen. There’s an evening performance at 7:30 but the 2pm matinee will be followed by a 20-minute talkback.