IFC’s Comedy Bang! Bang! is pulling out all the stops with its Christmas episode (Dec. 20, 10 p.m.), and that includes a sit-down interview with Santa Claus himself, played by Zach Galifianakis. But as host Scott Aukerman finds out, Santa knows not just when you’re sleeping and when you are awake, or the amounts of good and evil inside you. No, St. Nick sees much more than you ever feared.