PetaPoco is a tiny .NET data access layer inspired by Rob Conery's Massive project but for use with non-dynamic POCO objects. It came about because I was finding many of my projects that used SubSonic/Linq were slow or becoming mixed bags of Linq and CodingHorror....

Gendrame Addin for MonoDevelop,

OpenVP is a free and open-source platform for developing music visualizations, written in C# and developed primarily on Linux. The Tao Framework OpenGL bindings are used for effect rendering.

The high-level goal of OpenVP is to develop a platform-neutral, media-player-neutral framework for developing music visualizations. The framework should impose as few restrictions on creativity as possible while also providing a base that makes this flexibility easy to consume....

BooGame is an object oriented CLS-compliant, 2D game engine framework that provides high-level access to video, audio, keyboard, mouse, joystick, embedded scripting and various image formats. Written in C#, its target platforms are .NET 2.0 and Mono 2.0.

A tool for maintaining .NET Assembly versions across multiple files.,

A small validation library for .NET that uses a fluent interface and lambda expressions for building validation rules for your business objects.

Interact with Google Maps through C# or VB.NET. Built on Gaia Ajax, for full Ajax capabilities.

//asp.net markup
g:GMap
runat="server"
ID="GMap1"
CssClass="googleMaps"
Height="350px"
Width="450px"...

Lightweight framework for heavy lifting

With Evolutility, you can build database CRUD web applications for ASP.net and SQL Server simply by describing their metadata (UI and DB mapping)... without any hand coding necessary.

http://www.evolutility.org

Orizon is a framework intended to provide tools and facilities to test java sources for security flaws. The main goal is to detect common threats as described in Owasp top 10 vulnerability document.

Netris is a free, open source, clone of the popular Tetris(tm) game.

It's written in C# and uses SDL.NET
It runs on both Windows and Linux.

It serves as an example for beginning game developers or developers who want to get started with SDL.NET

Scores are submitted to the homepage, so users can compete with one another for high scores....