I wanted to build a demo for the Silverlight precon at the PDC showing off Silverlight 2’s support for duplex WCF services. I considered various themes for the demo, including stock tickers, sports scores, and weather data. But what I ultimately decided on is an unflattering statement about the state of our country: a national debt clock. Here’s the UI:

 National Debt Clock

When the app starts up, it connects to a WCF duplex service named DebtService. Approximately every 5 seconds, DebtService pushes a new national debt value down to the client. I based the numbers on actual national debt figures, so the clock is (sadly) reasonably correct. I have it running in one corner of my desktop now and find it more than a little depressing. The figure increased about $30 million in the time it took to type this blog entry.

Without a doubt, this is the saddest demo I’ve ever written.