The .NET Framework 3.5 Client Profile is a lightweight subset of the full .NET Framework 3.5 aimed to be deployed in Client machines. Therefore, it only have the assemblies that are commonly used on client boxes and does not contains any server or development related assemblies.
This framework subset weight just 27Mb against the 200Mb of [...]

This post is aimed to be a quick abstract for all the new C# language constructs introduced with the version 3.0.
Implicitly typed local variables
By using var keyword to define a local (does not work at class level) variable is not needed to define its type, the compiler will infer it.
Examples:
var i = 0; [...]