Although PHS is not a Google Apps school (yet), students in my social studies courses spent considerable time effectively collaborating with these tools throughout the year. They worked together to develop presentations, write and revise research papers, and even engage in Hangouts when necessary (and sometimes when not, but they are kids right?)
Here is a very brief video that my AP European History students put together explaining how they utilize Google Docs in class. (Click Here to View on YouTube)
I feel that this is just the tip of the iceberg regarding collaboration with Google Apps. There are so many innovate ways to learn with these tools, the possibilities seem limitless. I look forward to diving back into it this fall and learning along with the students.