I have just completed the first sprint, where we used Wave to collaboration.
One of the gadgets we used was Taskboardy, created by fzuppa. It works like a taskboard on a normal sprint tool, where you have your stories and tasks. It is possible to move the tasks forward from not started, to in progress and to complete. It is possible to drag the tasks from one phase to the next.
The idea of the gadget is really nice, you have one place to monitor your sprint.
The developers linked the gadget, because it made them cabable to see what was going on. It also provide lots of visibility on what is the different tasks we are working on.
The problem was that it is rather deficult to monitor what is going on. You cannot see which of the changes has happended since last time you look at the board, you can use the replay but it is a bit more complex. The board also have tendeny to become quite large, so it is deficult to make it work fully.
The plan was to complete a review every day until Christmas, if you have an Wave related application that, you feel should get a review drop a comment. I do hope there are enough gadgets/robots or other wave tools to describe.