A few hours ago, we shipped the release candidate of Silverlight 1.0 and an update for Silverlight 1.1 alpha. Steve Marx, inspired by the stories of Cakewalk implementing a music sequencer on 64-bit Windows, decided to see what he could do in a few minutes with the release candidate of Silverlight.
It's not quite Cakewalk, but it's fun and easy to use. When you make a drum sequence that you like, you can save it for other people to hear. He did the whole thing in Silverlight, ASP.NET, and ASP.NET AJAX. He'll be sharing more details about implementation, too.