Check out the Freakonomics Student's Guide here - it's definitely worth a look if you liked the book. And if you haven't read Freakonomics (or at least thumbed through it in a Barnes and Noble) then go check the book out first!
And other useful blogs to check out to keep your mind active:
- The few posts on the Small Giants blog.
- The Freakonomics blog.
- The Marginal Revolution blog.
These are just a few of the blogs I read everyday (throughout the day) though the Small Giants blog hasn't been kept up to date. Hope that helps!