The LinFu Framework is a set of libraries that extend the CLR by adding the following language features:

• Aspect-Oriented Programming
• Dynamic Proxies
• Late Binding
• Mixins
• Universal Event Handling
• Closures with Lambda Arguments
• Duck Typing
• Design by Contract

For more information, you can read the articles posted at this link:

http://www.codeproject.com/cs/library/LinFuPart1.asp