While checking out other blogs today, I ran across an interesting link provided by Alex Tabarrok on Marginal Revolution. I don't think it would work with my wife, either. Although it offers an interesting way to discuss both substitutes, and form utility as they pertain to value of goods. (Heck, scarcity might even fit in there someplace.) And that would provide a segue into the diamonds vs. water paradox on value and price.
Anyone have any thoughts out there? I would think two pieces of cardboard with "season tickets to (insert favorite team here)" might be an appropriate counter.