I agree that Google docs can be of great use in the classroom. I've posted this site once for a different reason, but I'm going to post it again because of it's two Google uses.
If you click the calendar link, it'll display a homework calendar that is shared by the teachers on that team. They each have a separate log in so when they add assignments, it's in their specific color. Currently, only December has updated assignments. Too many snow days have kept us out. Also, the quiz link uses a form from Google docs that allows students to take a quiz, and Google puts the answers into an excel sheet, which makes for easy assessing.