Microsoft Frameworks
ASP.Net MVC

The ASP.NET MVC Framework is a web application framework that implements the model-view-controller pattern. Based on ASP.NET, it allows software developers to build a Web application as a composition of three roles: Model, View and Controller. A model represents the state of a particular aspect of the application. Frequently, a model maps to a database table with the entries in the table representing the state of the application. A controller handles interactions and updates the model to reflect a change in state of the application, and then passes information to the view. A view accepts necessary information from the controller and renders a user interface to display that.

 
ADO Entity

ADO.NET Entity Framework abstracts the relational (logical) schema of the data that is stored in a database and presents its conceptual schema to the application. This abstraction eliminates the object-relational impedance mismatch that is otherwise common in conventional database-oriented programs.

 
nHibernate

NHibernate is an Object-relational mapping (ORM) solution for the Microsoft .NET platform: it provides a framework for mapping an object-oriented domain model to a traditional relational database. Its purpose is to relieve the developer from a significant portion of relational data persistence-related programming tasks.
NHibernate is free as open source software that is distributed under the GNU Lesser General Public License.
NHibernate is a port of the popular Java O/R mapper Hibernate to .NET.

 
Linq

Language Integrated Query is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages.
LINQ defines a set of method names (called standard query operators, or standard sequence operators), along with translation rules from so-called query expressions to expressions using these method names, lambda expressions and anonymous types. These can, for example, be used to project and filter data in arrays, enumerable classes, XML (LINQ to XML), relational database, and third party data sources. Other uses, which utilize query expressions as a general framework for readably composing arbitrary computations, include the construction of event handler.

 
Silverlight

Microsoft Silverlight is an application framework for writing and running rich Internet applications, with features and purposes similar to those of Adobe Flash. The run-time environment for Silverlight is available as a plug-in for most web browsers. While early versions of Silverlight focused on streaming media, current versions support multimedia, graphics and animation, and give developers support for CLI languages and development tools. Silverlight is also one of the two application development platforms for Windows Phone 7.

 
Drools.NET

Drools.NET is a Business Rules Engine (BRE) based on Charles Forgy's Rete algorithm. Developers can now exploit a powerful Rule Engine through a completely managed .NET code base! Drools.NET is based on Jboss Rules, and comes with all the features of that Rules Engine.