Back in february, Microsoft released a sample application for ficiticious company
DinnerNow.net to showcase it's new technologies like .NET 3.0 (WWF, WCF, WPF), Card Space, Windows mobile 5.0, .NetCF, and Ajax. This application uses all these technology to custom built the solution for the company. This is a pretty cool demo with lots of insights into new technology,
download source code to look behind the scenes.