Map lovers should check out the webpage for the Norman B. Levanthal Map Center at the Boston Public Library. The library has imaged many highlights from their 200,000+ collection of maps and atlases from all times and places. Start with the virtual tours for an overview. Teachers should also see the Educational Resources for teaching ideas (such as the Darfur exercises).
On the topic of maps, we looked at the wonderful Strange Maps blogs a few months ago. If you haven't been in a while, give it another look. It's still going with many fun curiousities, such as the mysterious East German island near Cuba.