I joined the virtual world Second Life a couple of years ago, but never really got into it -- I mostly just flew around looking at things, and the only people I ever saw were playing casino games. I'm always amazed when I hear how people are using the virtual world to collaborate and work with others.
Did you know you can also collaborate on documents in Second Life? Here's a great video on EtherPad Real Time in World Text Collaboration from the Second Life English Blog. EtherPad is one of the new document creation sites that literally allows you to see changes to the text in real time; it's not a full-featured document editor -- it's pretty much just text -- but it's great in terms of collaboration possibilities.
Why use it in Second Life? A couple of reasons; first, your group can discuss the document as it's being edited, via the Second Life chat feature. You can also invite an unlimited number of people to review the document without giving them actual editing access. All they need is a Second Life account.
And I think that it's not just EtherPad that allows this functionality -- it's any site that publishes a URL for its document. While Google Docs don't have their own dedicated URL, Google Spreadsheets do -- so you can probably work on spreadsheets within Second Life as well.