Another common classroom procedure that Google Docs can enhance is error correction. During the lesson, if you notice that students are making particular speaking or writing errors, you can collect them on a Google Doc and then share them with the group either at the end of the lesson or for homework. I would set the sharing settings so that students could only comment on the mistakes rather than edit them, and then they could work in pairs/groups to make suggestions in the margins as to what the correct answer is.