Yep. Our book club read 'The Lost Symbol' this month. It's a national (maybe international?) bestseller, and it's set in our city. Every tourist is going to ask how to find the 'secret' buildings, so we might as well know what they're talking about.
To be honest, I've read both 'Angels and Demons' and 'The Davinci Code.' I thought they were fun, easy reads, interesting, but not to be taken too seriously. This book was the same. The plot was very similar to the other two books, which is ok, since that's about what I expected.
It actually was fun to read a book like this that is set in your own city. Lots of the highlighted sights are within just a few blocks of my house, and they do have interesting histories. Though I don't buy into conspiracy theories, I thought you could still get the 'stop and smell the roses' lesson from reading this book. It's fun to take the time to notice your surroundings and learn about the history of the city and its various buildings, and this book reminded me that there are lots of fun things still to be discovered and learned about in DC.