Today’s lunchtime was a video from Øredev 2010 by two people who work with approx 100 developers. More than just handling the scrum of scrums, they talk about real-world solutions to making their scrum teams work well together.
Though the most we had was 3 scrum teams on one project for a while, but even there we could have used some of the techniques described to help foster knowledge and code sharing, and create well oiled teams and a better product.
Very good value watching this, even if you have only one scrum team in operation.
For presentation notes see: http://oredev.org/2010/sessions/brown-bags-circles-top-code-and-lanterns-knowledge-management-in-scrum
a link to the video of the presentation is at the bottom of the page linked above.