Check out Soma's blog today: http://blogs.msdn.com/somasegar/archive/2007/04/15/silverlight-the-next-generation-web-media-experiences.aspx

He announced a new project called Silverlight that enables amazingly cool cross browsers, cross platform web apps to be written.  I've seen some of the demos and they are stunning.  I suspect over the next week or two we'll see lots of demos posted to give you an idea of what you can do.  You can check out http://www.microsoft.com/silverlight for more information and a video of the kinds of things you can do (OK, I can't do them because I have the artistic ability of your average 3 year old, but it's amazing to see what others can do with it :))

Brian