Using Gmail in middle and high school.

In middle school, Gmail could be used, along with Google Groups, to have a forum with students about a topic. The teacher could post a question to the group and all students could respond to it by emailegitimate. All responses would be kept in the Google Group, as well as being sent to group members, in the form of a daily digest, or as an email for each response.
In high school, combine the Forms application in Google Docs with Gmail to create an interface for gathering data and information.  It could be especially useful in science for gathering lab data, social science for surveys, for extra-curricular elections, and other classes for gathering ideas during brainstorming. Students would first create a form in a a Google Docs and then send the form to themselves. They would then forward the message from their email after adding instructions or guestions above the form.