Not sure exactly WHAT episode it will be on this season (2009 season), but there will be an episode where someone wears a kilt. It wasn't one of the regular "Office" cast, but instead is a pretty established actor in his own right who appears on the episode... Robert Pine (best known as Sgt. Joseph Getraer from CHIPS). Here's a picture I received from the costume director from The Office of him in our kilt (and other accessories we supplied):