Orchard is a free, open source, community-focused Content Management System built on the ASP.NET MVC platform.

Http Library for C#

Open Source PHP Framework (originally from EllisLab)

FlyJSONP is a small JavaScript library, that allows you to do cross-domain GET and POST requests, with JSON response.

A C# implementation of the OpenID, OAuth protocols

NLog - Advanced and Structured Logging for Various .NET Platforms

.NET (WPF and Windows Forms) bindings for the Chromium Embedded Framework

Dapper - a simple object mapper for .Net

ARCHIVED

The official Umbraco Documentation

Open source code base for enabling software innovation in medical imaging

Open source code base for enabling software innovation in imaging. The extensible and robust platform includes viewing, archiving, management, workflow and distribution of images as well as an open…

It's a presentation framework based on the power of CSS3 transforms and transitions in modern browsers and inspired by the idea behind prezi.com.