Ask them what they think about the TechCrunch and Kotaku redesigns. If they actually like them, let them go on for a few more minutes, thank them for their time, escort them out, and throw their application away.

Those redesigns are everything that's wrong with young designers (me included). Looks over usability, creative over predictable is the WRONG way to design. Good design is about usability and usability is about predictability, not over complicating what isn't broken for the sake making it different, not hiding elements and loading up info on rollovers just to give the site a "cold, heartless, minimistic, look at me I'm the next Steve Jobs, look", not segregating information pointlessly.

If they can't tell you what's wrong with the designs in detail, let them go.