This looks like some serious fun: http://startupweekend.com/
What a great idea! Get a bunch of interesting folks in the room, come up with an idea and build it over a weekend. The idea they came up with sounds really cool - a widget based polling service. I can definitely think of use cases where that would be very useful.
An interesting aspect for me as I follow along are the choices being made on the dev side. EC2 for compute power - no brainer. S3 for backup - yup. Facebook is the obvious choice for the first extension. Spring and Flex though? I would of thought they would of gone with RoR for sure.
The revenue model will be ad based, by the looks of the latest (Sat. night) mockups at least.