Demos

Demos are a great way to get everyone familiar with what's been accomplished.  This is particularly the case with larger organizations (those with multiple Agile teams).  I would highly encourage a single demo for teams working on different parts of the same product.  Not only does it keep everyone in the loop, it encourages a lot of synergy.  Now that they've done that, what if we did this...

Demos are a great way to get feedback.  They generate lots of conversations and good ideas for the next iteration.  This worked or this didn't work or what if we did this...  Encourage questions and discussion.  Know when to spin those off into separate meetings.

To be effective, demos need to be interesting.  The best way I've found to do this is to focus on customer value.  Show how the customer would accomplish things given the new features. And emphasize why that's important.  This keeps the teams grounded in thinking about things from a customer point of view.

We generally do acceptance before the demo.  That way we can focus on the demonstration itself rather than administrative aspects / too much detail.

Demos are a great way to keep the teams energized. They help to show how much progress you're making.  Everyone likes progress.  Demos are a way to make that progress obvious.