Show of the week: Family Tree

The king of the mockumentary is back. In films like Best in Show and Waiting for Guffman, director Christopher Guest refined the blueprint for much of today’s TV comedy by mixing improv acting with documentary-style interviews. Now he’s putting the same format to use in his own very funny series, starring Bridesmaids’ Chris O’Dowd as a lovable loser who starts digging into his family genealogy. Various members of Guest’s stock company of actors, including Michael McKean, Nina Conti, Fred Willard, and Ed Begley Jr., help fill out the cast. Sunday, May 12, at 10:30 p.m., HBO