A: When a bookstore becomes a destination when you're traveling.
I had to go to Portland for work and while checking Mapquest to see how far the hotel was from the office, I noticed a bookstore listed on the map. I thought that was unusual - that a bookstore would appear like that. But it turns out that Powell's isn't just any bookstore - it's "the world's largest bookstore" (according to their website, anyway). And it was only a few blocks from the hotel! Cool!