However, the gem is definitely Destroy All Invaders, pictured above. The game uses Windows Live Maps Virtual Earth API, letting you choose any location on the planet and putting your helicopter above its satellite imagery. You fly around the map, shooting down UFOs. This is a brilliant use of both Silverlight and the Windows Live Maps API, created by Andy Beaulieu. Great job, man!
For most of these, the source code is available, so if you want to create a Windows Live Maps-based Silverlight game, check out Andy’s code.