Take a completed model or two, a couple of kits to show what the un-started product looks like, reference material (books, mags) for researching your subject. A few supplies like paint , glue, hobby tools, to show what one needs to get started, a couple copies of Model Cars to pass around. Just tell your story about what interests you in the hobby and what you derive out of it. Maybe some enlarged photos showing the process of building. Plus a lovely assistant in a bikini...uh, just kidding on that part.