Role-playing is The Office's way of demonstrating that practice makes perfect, and Dwight and Jim's performance was comedic perfection. Jim played the client named Mr. Buttlicker while Dwight played the paper salesperson, and each role-player had his own pretend phone. Michael, of course, moderated the whole thing terribly.
My first experience with role-playing at work was during college when I was waitressing — I didn't like it then, and I still despise it. Have you had to role-play at work?