Bob Corrigan pointed this one out to me. Say what you will about Microsoft, this is a fine scenario-based demo.
If you can't see the embedded video, try here.
Whenever I encounter a new company or product, I immediately want to hear a story about how the product will be used. Not vague explanations of how someone might want to do something and not how it will create synergy. Give me an example of its use!
Bob writes in nice persona-driven demo:
Sometimes product managers leave the "marketing stuff" up to the "marketing people". When it comes to how your products are demonstrated, don't let this happen. Make sure you connect capabilities to value by grounding them in problems people have, and how you help them solve those problems.