This Week: Eric Idle of “Monty Python” and “Spamalot” leads us in a singalong… Writer Jon Ronson plays sidekick to a real-life superhero…Folk icon Iris DeMent shares a homey dinner party soundtrack…Adam Pally of TV’s “Happy Endings” revisits his rocky beginnings…And kale invades Thanksgiving…. Plus, the birth of the leotard, the “King” of new music, and video games NOT named “Halo.”