Head First Design Patterns - Code Examples in C#
The only thing which bothered me while reading this book (Head First Design Pattern) was the code which was provided in Java.
I was very happy to learn that this is no longer an issue because now you can download all the codes in you native C# Language that too in Framework 4.0 :-)
You can download the codes from codeplex using the link below.
http://hfpatternsincsharp.codeplex.com/