As I had mentioned in a previous post, one web site that I recommend visiting for more educational family travel ideas is Home & Abroad. This site provides some great information on some of the most popular travel destinations and also offers some fun and educational activity suggestions for specific locations. I know they are great because I have written several of the articles for the site!
I am not just tooting my own horn, though, Home and Abroad employs a number of different city experts and activity writers in order to create a comprehensive site filled with travel ideas and tips. It even includes a travel planner that allows you to create your own itinerary, which you can create based on a specific theme if you like.
I definitely recommend checking this site out. I know from experience that the folks running the site are good people and they have a true interest in helping families enjoy a better vacation experience.