The free, open source and Mono-based implementation of Silverlight.,

libdmtx is a software library that enables programs to read and write Data Matrix 2D barcodes. It runs natively on several platforms, and can be accessed by multiple languages. The package also provides fully featured command line utilities.

Formerly known as DotNetOpenId, this library brings easy and flexible OpenID, OAuth and InfoCard to the .NET platform

Please visit our official site at http://www.dotnetopenauth.net/

• OpenID 1.x/2.0 support for both Providers and Relying Parties...

SubSonic is a toolset that helps a website build itself. It brings some of the fun and elegance of Ruby on Rails to ASP.NET.

ORM configuration by code.

There are times when a simple piece of code seems to have a soul.

ELMAH (Error Logging Modules and Handlers) is an application-wide error logging facility that is completely pluggable. It can be dynamically added to a running ASP.NET web application, or even all ASP.NET web applications on a machine, without any need for re-compilation or re-deployment....

GtkSharp is a C# binding for Gtk+,

Cecil is a library written by Jb Evain (http://evain.net/blog/) to generate and inspect programs and libraries in the ECMA CIL format.

In simple English, with Cecil, you can load existing managed assemblies, browse all the contained types, modify them on the fly and save back to the disk the modified assembly....

Gendarme is a extensible rule-based tool to find problems in .NET applications and libraries. Gendarme inspects programs and libraries that contain code in ECMA CIL format (Mono and .NET) and looks for common problems with the code, problems that compiler do not typically check or have not historically checked....

db4o is an object database available for Java and for .NET, including CompactFramework and Mono. Features include ACID transactions, automatic class schema recognition, Native Queries, query-by-example, S.O.D.A. object querying API, callback methods, memory files, cascade-on-delete and cascade-on-update. db4o runs in embedded local mode and in multi-transactional client/server mode....