1. Spring.NET - Application Frameowrk
website: http://www.springframework.net/
Led and sustained by SpringSource, Spring.NET is an open source application framework that makes building enterprise .NET applications easier. Providing components based on proven design patterns that can be integrated into all tiers of your application architecture, Spring helps increase development productivity and improve application quality and performance.
2. Castle - Application Framwork
website: http://www.castleproject.org/
Castle is an open source oject for .net that aspires to simplify the development of enterprise and web applications. Offering a set of tools (working together or independently) and integration with others open source projects, castle helps you get more done with less code and in less time.
3. BlogEngine.NET - Blog
website:http://blogengine.codeplex.com/
BlogEngine.NET is a full-featured blogging platform that is a breeze to set up, customize, and use. BlogEngine.NET works with your choice of data source; you may use SQL Server, or you may take the plug’n’play approach using XML files.
4. ScrewTurn - Wiki
website: http://www.screwturn.eu/Wiki.ashx
ScrewTurn Wiki is a fast, powerful and simple ASP.NET wiki engine, installs in a matter of minutes and it’s available in different packages, fitting every need. It’s even free and open source.
5. Cuyahoga - CMS
website: http://www.cuyahoga-project.org/
Cuyahoga is an open source .NET web site framework. It provides content management capabilities and has a modular approach. Currently it works with MS .NET 2.0-3.5 with SQL Server, PostgreSQL or MySQL as database backend. Also, Mono is fully supported.The main goal of the project is to show .NET developers that there is a different way of building web applications than the well known sample applications. Although the project is targeted primarily at .NET developers, anybody interested can download the source and start playing.
6. Quartz.NET - Enterprise Job Scheduler for .NET Platform
website: http://quartznet.sourceforge.net/
Quartz.NET is a full-featured, open source job scheduling system that can be used from smallest apps to large scale enterprise systems.
7. NHibernate - Object/Relationship Mapper for .NET
website:http://sourceforge.net/projects/nhibernate/
.NET port of the excellent Java Hibernate which provides Object/Relational mapping to persist objects in a relational database.
8. NUnit - Unit-Testing Framework
website: http://www.nunit.org/index.php
NUnit is a unit-testing framework for all .Net languages. Initially ported from JUnit, the current production release, version 2.4, is the fifth major release of this xUnit based unit testing tool for Microsoft .NET. It is written entirely in C# and has been completely redesigned to take advantage of many .NET language features, for example custom attributes and other reflection related capabilities. NUnit brings xUnit to all .NET languages.
9. CruiseControl.NET - Automated continuous integrated server.
website:http://confluence.public.thoughtworks.org/display/CCNET
CruiseControl.NET is an Automated Continuous Integration server, implemented using the Microsoft .NET Framework.10. BugNET -Open source issue tracking & project management
website:http://www.bugnetproject.com/
BugNET is an issue tracking and project issue management solution built using the ASP.NET web application framework. Email notifications, reporting and per project configuration of fields and values allows efficient management of bugs, feature requests, and other issues for projects of any scale.