flow

I read something a few months ago just in the newspaper about the concept of flow and I was glad to have a name for something I have always valued. It is what I love about teaching--it focuses me so completely that when I was pregnant with my second child and on partial bed rest and very uncomfortable, I kept teaching one course because teaching was the only time I didn't feel physically miserable, when I could forget I was pregnant. (Though my students couldn't--I had a 10 lb baby and I was really big.) Today I am happy being busy with a series of projects, both related to my own research and preparing a workshop I will teach tomorrow. Anyone know any good web sites for historical maps for use in teaching?