Sculpture is a .NET open source Model-Driven Development code generation framework... can model your application components, and then transform this model to deployable components ... comes with ready-made molds like NHibernate, LINQ, WCF, etc
Describes all of the GoF patterns (Creational / Structural / Behavioral) using 2 UML diagrams: One presenting the pattern, one for an example. There's not a lot of verbal description though.