As I recall, we tried a collaboration using Google Docs last August during staff development. It did not go well with 4 or 5 groups participating in real time. To me this sounds great, but the idea of real time edits by more than one person seems destined to pull the Chaos Theory lever - you might end up all cherries, but then again, might not.
My favorite was the Google Forms app. I immediately thought of Quinton Freeman's "I need/I provide" spreadsheet for testing time. I liked the quiz generator - I currently have seniors write potential test questions from their notes after a lecture (notes have limited use for prelims, but a list of possible test questions, that's a way to prepare). In future, I could see students taking notes, generating their own questions online, then I would cull these to produce quizzes. I could see pointing out things they missed in the lecture (adding questions they missed), a push for them to take better notes for the next topic.
I just had to laugh. I got into Google Apps, thinking "this is new," and got the message "Google Docs is being replaced by Google Drive." Talk about a quick change. Then I realized I had been there before, when I recognized the special ed documents I had received and been trained on earlier in the year! If you don't use it, you lose it. That raises a question - when will last year's SpEd docs be purged?
I could see producing a department equipment purchase/replacement spreadsheet by sending forms to team members with description, source, unit price, number required, etc.
It's interesting, learning to use an iPAD, I can see just how badly Google wants to compete with Apple. Somebody gonna win, somebody gonna lose.