In the official season-two trailer of Showtime's Masters of Sex, one of the best TV shows you're (probably) not watching, Virginia Johnson (Lizzy Caplan) says in a sing-song voice, "Sex: Enjoy it if and when you can ... But keep your heart out of it." Clearly this will not be advice she takes for herself, as her relationship with her sexologist boss Dr. Masters (Michael Sheen) gets increasingly, shall we say, complicated. Not seen in the trailer are Sarah Silverman and Christian Borle, who have signed on to appear in the season as "Helen" and Francis Masters, Dr. Masters's brother. The show starts up again on July 13, which means you still have a couple of weeks to get into it.