The best kept Visual Studio 2008 secret is the built in code generator called T4 that lets you define a DSL to write code, xml or whatever for you to be included at compile time. Yes, that's right. This is quite useful for generating e.g. DAL or tedious verbose implementations, like immutable classes. So as an example I wrote a T4 template for the latter. To use it add the template to a C# project, and create a file called e.g. Size.tt with the following contents:
<#@ include file="Immutable.tt" #> <#= Immutable.Struct(Host, "float Width;float Height") #>
As you save the files, you will see that a .cs file is created below the .tt file, and the struct have been generated in the project's default namespace. The struct is partial so you can easily extend it with attributes, base classes or additional methods in other class files. The template can be found at http://t4.codeplex.com/. I hope you find it useful or at least feel inspired to make some of your own.