~ The Usborne Encyclopedia of World Religions; this book is internet-linked so you have suggested websites with activities for the different religions discussed in the book.
~ The Joshua Project; tons of information for just about any people group you could ever imagine. This link gives you several options for added an unreached people of the day button to your blog.
~ Global Prayer Digest; daily prayer topics for different countries
~ Ann Voskamp and Tonia Peckover are the authors of "A Child's Geography". I haven't used this, but I hear it is highly recommended.
~ YWAM has a unit study curriculum guide titled "Christian Heroes: Then & Now." I haven't used it but have heard positive things about it from friends who have.