3-D Drawing Surface, new in Silverlight 5 Beta
Link: What's New in Silverlight 5 Beta
The big one for many people is the ability to be able to create a 3D drawing surface using the DrawingSurface Class. This is a big deal for the game design folks!
Here is a link (as of June 8, 2011) that walks you through how to create a 3D Silverlight app:
Walkthrough: Creating and Animating a 3D Textured Cube in Silverlight
)
<StackPanel Margin="35" Background="Gray">
<StackPanel.Projection>
<PlaneProjection RotationX="-35" RotationY="-35" RotationZ="15" />
</StackPanel.Projection>
<TextBlock Margin="10">Type Something Below</TextBlock>
<TextBox Margin="10"></TextBox>
<Button Margin="10" Content="Click" Width="100" />
</StackPanel>
Source Code (for the cube below
Pretty cool.