Code samples for Silverlight using C# and XAML:
Monotone
A graphics demo in XAML and C# with MP3 audio.
Start here. Source here.
Digger
Silverlight version of a Boulderdash game. Use cursor keys, ESC to restart, SPACE to jump to the next level.
Start here.
Inplay
An in-page audio and video player with position and volume control.
Start here. Source here.