Check out Microsoft Popfly which was released Alpha today and is powered by Microsoft Silverlight! You can easily create mashups, gadgets, and web applications using visual tools without writing any code. To generate an application you connect services such as Live Spaces, Xbox Live, Flickr, and Virtual Earth by clicking and dragging on blocks and connecting them. You can also develop your own custom blocks. Check out the 15 minute Popfly screencast for more details.